21211550400 has 84 divisors (see below), whose sum is σ = 69591577352. Its totient is φ = 5656412160.

The previous prime is 21211550387. The next prime is 21211550411. The reversal of 21211550400 is 405511212.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2204737 + ... + 2214336.

Almost surely, 2^21211550400 is an apocalyptic number.

21211550400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21211550400 is an abundant number, since it is smaller than the sum of its proper divisors (48380026952).

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

21211550400 is a wasteful number, since it uses less digits than its factorization.

21211550400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4419098 (or 4419083 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 21.

The spelling of 21211550400 in words is "twenty-one billion, two hundred eleven million, five hundred fifty thousand, four hundred".