211515055551 has 24 divisors (see below), whose sum is σ = 317013975824. Its totient is φ = 135784512000.

The previous prime is 211515055541. The next prime is 211515055589. The reversal of 211515055551 is 155550515112.

211515055551 is a `hidden beast` number, since 2 + 1 + 1 + 5 + 1 + 50 + 55 + 551 = 666.

It is not a de Polignac number, because 211515055551 - 2¹⁴ = 211515039167 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211515055501) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3241825 + ... + 3306426.

Almost surely, 2^211515055551 is an apocalyptic number.

211515055551 is a deficient number, since it is larger than the sum of its proper divisors (105498920273).

211515055551 is a wasteful number, since it uses less digits than its factorization.

211515055551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6548391 (or 6548388 counting only the distinct ones).

The product of its (nonzero) digits is 31250, while the sum is 36.

The spelling of 211515055551 in words is "two hundred eleven billion, five hundred fifteen million, fifty-five thousand, five hundred fifty-one".