21103356537 has 6 divisors (see below), whose sum is σ = 30482626122. Its totient is φ = 14068904352.

The previous prime is 21103356523. The next prime is 21103356577. The reversal of 21103356537 is 73565330112.

21103356537 is a `hidden beast` number, since 2 + 110 + 3 + 3 + 5 + 6 + 537 = 666.

It can be written as a sum of positive squares in only one way, i.e., 19504636281 + 1598720256 = 139659^2 + 39984^2 .

It is not a de Polignac number, because 21103356537 - 2⁷ = 21103356409 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21103356577) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1172408688 + ... + 1172408705.

It is an arithmetic number, because the mean of its divisors is an integer number (5080437687).

Almost surely, 2^21103356537 is an apocalyptic number.

It is an amenable number.

21103356537 is a deficient number, since it is larger than the sum of its proper divisors (9379269585).

21103356537 is a wasteful number, since it uses less digits than its factorization.

21103356537 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2344817399 (or 2344817396 counting only the distinct ones).

The product of its (nonzero) digits is 56700, while the sum is 36.

Adding to 21103356537 its reverse (73565330112), we get a palindrome (94668686649).

The spelling of 21103356537 in words is "twenty-one billion, one hundred three million, three hundred fifty-six thousand, five hundred thirty-seven".