21351222501 has 32 divisors (see below), whose sum is σ = 33207398400. Its totient is φ = 11950303680.

The previous prime is 21351222499. The next prime is 21351222527. The reversal of 21351222501 is 10522215312.

It is not a de Polignac number, because 21351222501 - 2¹ = 21351222499 is a prime.

It is a super-3 number, since 3×21351222501³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21351222551) 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, 271290 + ... + 341028.

It is an arithmetic number, because the mean of its divisors is an integer number (1037731200).

Almost surely, 2^21351222501 is an apocalyptic number.

21351222501 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21351222501 is a deficient number, since it is larger than the sum of its proper divisors (11856175899).

21351222501 is a wasteful number, since it uses less digits than its factorization.

21351222501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70049.

The product of its (nonzero) digits is 1200, while the sum is 24.

Adding to 21351222501 its reverse (10522215312), we get a palindrome (31873437813).

The spelling of 21351222501 in words is "twenty-one billion, three hundred fifty-one million, two hundred twenty-two thousand, five hundred one".