21123113320 has 32 divisors (see below), whose sum is σ = 47663217000. Its totient is φ = 8425029888.

The previous prime is 21123113287. The next prime is 21123113327. The reversal of 21123113320 is 2331132112.

It can be written as a sum of positive squares in 4 ways, for example, as 15741717156 + 5381396164 = 125466^2 + 73358^2 .

It is a super-2 number, since 2×21123113320² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21123113327) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 742599 + ... + 770518.

Almost surely, 2^21123113320 is an apocalyptic number.

21123113320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21123113320 is an abundant number, since it is smaller than the sum of its proper divisors (26540103680).

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

21123113320 is a wasteful number, since it uses less digits than its factorization.

21123113320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1513477 (or 1513473 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 19.

Adding to 21123113320 its reverse (2331132112), we get a palindrome (23454245432).

The spelling of 21123113320 in words is "twenty-one billion, one hundred twenty-three million, one hundred thirteen thousand, three hundred twenty".