21276402516 has 72 divisors (see below), whose sum is σ = 56175552160. Its totient is φ = 7041066912.

The previous prime is 21276402509. The next prime is 21276402523. The reversal of 21276402516 is 61520467212.

It is a happy number.

21276402516 is a `hidden beast` number, since 2 + 1 + 2 + 7 + 640 + 2 + 5 + 1 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (21276402509) and next prime (21276402523).

It is a super-2 number, since 2×21276402516² (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 congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 56370 + ... + 213846.

Almost surely, 2^21276402516 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 21276402516, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28087776080).

21276402516 is an abundant number, since it is smaller than the sum of its proper divisors (34899149644).

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

21276402516 is a wasteful number, since it uses less digits than its factorization.

21276402516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157635 (or 157621 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

Adding to 21276402516 its reverse (61520467212), we get a palindrome (82796869728).

The spelling of 21276402516 in words is "twenty-one billion, two hundred seventy-six million, four hundred two thousand, five hundred sixteen".