21251122776 has 96 divisors (see below), whose sum is σ = 62088586560. Its totient is φ = 6527609856.

The previous prime is 21251122769. The next prime is 21251122807. The reversal of 21251122776 is 67722115212.

It is a super-2 number, since 2×21251122776² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21251122776.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 535905 + ... + 574191.

It is an arithmetic number, because the mean of its divisors is an integer number (646756110).

Almost surely, 2^21251122776 is an apocalyptic number.

21251122776 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21251122776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31044293280).

21251122776 is an abundant number, since it is smaller than the sum of its proper divisors (40837463784).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21251122776 is a wasteful number, since it uses less digits than its factorization.

21251122776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38905 (or 38898 counting only the distinct ones).

The product of its digits is 23520, while the sum is 36.

Adding to 21251122776 its reverse (67722115212), we get a palindrome (88973237988).

The spelling of 21251122776 in words is "twenty-one billion, two hundred fifty-one million, one hundred twenty-two thousand, seven hundred seventy-six".