21796697538 has 192 divisors, whose sum is σ = 61756992000. Its totient is φ = 5634830880.

The previous prime is 21796697537. The next prime is 21796697539. The reversal of 21796697538 is 83579669712.

21796697538 is a `hidden beast` number, since 2 + 1 + 7 + 9 + 6 + 6 + 97 + 538 = 666.

It is an interprime number because it is at equal distance from previous prime (21796697537) and next prime (21796697539).

It is a super-2 number, since 2×21796697538² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (21796697537) by changing a digit.

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 95 ways as a sum of consecutive naturals, for example, 6605413 + ... + 6608711.

It is an arithmetic number, because the mean of its divisors is an integer number (321651000).

Almost surely, 2^21796697538 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21796697538, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30878496000).

21796697538 is an abundant number, since it is smaller than the sum of its proper divisors (39960294462).

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

21796697538 is a wasteful number, since it uses less digits than its factorization.

21796697538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3562 (or 3549 counting only the distinct ones).

The product of its digits is 34292160, while the sum is 63.

The spelling of 21796697538 in words is "twenty-one billion, seven hundred ninety-six million, six hundred ninety-seven thousand, five hundred thirty-eight".