21531213110 has 24 divisors (see below), whose sum is σ = 42599774448. Its totient is φ = 7829531600.

The previous prime is 21531213107. The next prime is 21531213113. The reversal of 21531213110 is 1131213512.

It is an interprime number because it is at equal distance from previous prime (21531213107) and next prime (21531213113).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21531213113) 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 11 ways as a sum of consecutive naturals, for example, 8895986 + ... + 8898405.

It is an arithmetic number, because the mean of its divisors is an integer number (1774990602).

Almost surely, 2^21531213110 is an apocalyptic number.

21531213110 is a deficient number, since it is larger than the sum of its proper divisors (21068561338).

21531213110 is a wasteful number, since it uses less digits than its factorization.

21531213110 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17794420 (or 17794409 counting only the distinct ones).

The product of its (nonzero) digits is 180, while the sum is 20.

Adding to 21531213110 its reverse (1131213512), we get a palindrome (22662426622).

The spelling of 21531213110 in words is "twenty-one billion, five hundred thirty-one million, two hundred thirteen thousand, one hundred ten".