21012403122 has 12 divisors (see below), whose sum is σ = 45526873470. Its totient is φ = 7004134368.

The previous prime is 21012403079. The next prime is 21012403157. The reversal of 21012403122 is 22130421012.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20463016401 + 549386721 = 143049^2 + 23439^2 .

It is a super-2 number, since 2×21012403122² (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: 1167355729 = 21012403122 / (2 + 1 + 0 + 1 + 2 + 4 + 0 + 3 + 1 + 2 + 2).

It is a junction number, because it is equal to n+sod(n) for n = 21012403095 and 21012403104.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 583677847 + ... + 583677882.

Almost surely, 2^21012403122 is an apocalyptic number.

21012403122 is an abundant number, since it is smaller than the sum of its proper divisors (24514470348).

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

21012403122 is a wasteful number, since it uses less digits than its factorization.

21012403122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1167355737 (or 1167355734 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 21012403122 its reverse (22130421012), we get a palindrome (43142824134).

The spelling of 21012403122 in words is "twenty-one billion, twelve million, four hundred three thousand, one hundred twenty-two".