21206521251650 has 48 divisors (see below), whose sum is σ = 46178493137280. Its totient is φ = 7093470518400.

The previous prime is 21206521251563. The next prime is 21206521251653. The reversal of 21206521251650 is 5615212560212.

It is not an unprimeable number, because it can be changed into a prime (21206521251653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 738888830 + ... + 738917529.

It is an arithmetic number, because the mean of its divisors is an integer number (962051940360).

Almost surely, 2^{21206521251650} is an apocalyptic number.

21206521251650 is an abundant number, since it is smaller than the sum of its proper divisors (24971971885630).

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

21206521251650 is a wasteful number, since it uses less digits than its factorization.

21206521251650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1477806419 (or 1477806414 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 38.

The spelling of 21206521251650 in words is "twenty-one trillion, two hundred six billion, five hundred twenty-one million, two hundred fifty-one thousand, six hundred fifty".