21951312936 has 128 divisors (see below), whose sum is σ = 64628551680. Its totient is φ = 6081889536.

The previous prime is 21951312931. The next prime is 21951312949. The reversal of 21951312936 is 63921315912.

It is a super-2 number, since 2×21951312936² (a number of 21 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (21951312931) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1902561 + ... + 1914063.

It is an arithmetic number, because the mean of its divisors is an integer number (504910560).

Almost surely, 2^21951312936 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21951312936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32314275840).

21951312936 is an abundant number, since it is smaller than the sum of its proper divisors (42677238744).

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

21951312936 is a wasteful number, since it uses less digits than its factorization.

21951312936 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11863 (or 11859 counting only the distinct ones).

The product of its digits is 87480, while the sum is 42.

It can be divided in two parts, 2195 and 1312936, that added together give a palindrome (1315131).

The spelling of 21951312936 in words is "twenty-one billion, nine hundred fifty-one million, three hundred twelve thousand, nine hundred thirty-six".