21201021012 has 24 divisors (see below), whose sum is σ = 49720166496. Its totient is φ = 7031133088.

The previous prime is 21201021007. The next prime is 21201021031. The reversal of 21201021012 is 21012010212.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4481778 + ... + 4486505.

It is an arithmetic number, because the mean of its divisors is an integer number (2071673604).

Almost surely, 2^21201021012 is an apocalyptic number.

It is an amenable number.

21201021012 is an abundant number, since it is smaller than the sum of its proper divisors (28519145484).

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

21201021012 is a wasteful number, since it uses less digits than its factorization.

21201021012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8968487 (or 8968485 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21201021012 its reverse (21012010212), we get a palindrome (42213031224).

The spelling of 21201021012 in words is "twenty-one billion, two hundred one million, twenty-one thousand, twelve".