21002512122 has 12 divisors (see below), whose sum is σ = 45505442970. Its totient is φ = 7000837368.

The previous prime is 21002512117. The next prime is 21002512127. The reversal of 21002512122 is 22121520012.

21002512122 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (21002512117) and next prime (21002512127).

It can be written as a sum of positive squares in only one way, i.e., 14520491001 + 6482021121 = 120501^2 + 80511^2 .

It is a super-2 number, since 2×21002512122² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 1166806229 = 21002512122 / (2 + 1 + 0 + 0 + 2 + 5 + 1 + 2 + 1 + 2 + 2).

It is a junction number, because it is equal to n+sod(n) for n = 21002512095 and 21002512104.

It is not an unprimeable number, because it can be changed into a prime (21002512127) 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, 583403097 + ... + 583403132.

Almost surely, 2^21002512122 is an apocalyptic number.

21002512122 is an abundant number, since it is smaller than the sum of its proper divisors (24502930848).

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

21002512122 is a wasteful number, since it uses less digits than its factorization.

21002512122 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1166806237 (or 1166806234 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The spelling of 21002512122 in words is "twenty-one billion, two million, five hundred twelve thousand, one hundred twenty-two".