21215154454550 has 48 divisors (see below), whose sum is σ = 45113763948000. Its totient is φ = 7271120943360.

The previous prime is 21215154454547. The next prime is 21215154454567. The reversal of 21215154454550 is 5545445151212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10062719 + ... + 11987018.

It is an arithmetic number, because the mean of its divisors is an integer number (939870082250).

Almost surely, 2^{21215154454550} is an apocalyptic number.

21215154454550 is an abundant number, since it is smaller than the sum of its proper divisors (23898609493450).

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

21215154454550 is a wasteful number, since it uses less digits than its factorization.

21215154454550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22052505 (or 22052500 counting only the distinct ones).

The product of its (nonzero) digits is 800000, while the sum is 44.

The spelling of 21215154454550 in words is "twenty-one trillion, two hundred fifteen billion, one hundred fifty-four million, four hundred fifty-four thousand, five hundred fifty".