215881911 has 12 divisors (see below), whose sum is σ = 356376592. Its totient is φ = 123361056.

The previous prime is 215881909. The next prime is 215881931. The reversal of 215881911 is 119188512.

It is not a de Polignac number, because 215881911 - 2¹ = 215881909 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 (215881901) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1713286 + ... + 1713411.

Almost surely, 2^215881911 is an apocalyptic number.

215881911 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

215881911 is a deficient number, since it is larger than the sum of its proper divisors (140494681).

215881911 is a wasteful number, since it uses less digits than its factorization.

215881911 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3426710 (or 3426707 counting only the distinct ones).

The product of its digits is 5760, while the sum is 36.

The square root of 215881911 is about 14692.9204380885. The cubic root of 215881911 is about 599.8906384013.

The spelling of 215881911 in words is "two hundred fifteen million, eight hundred eighty-one thousand, nine hundred eleven".