215801391 has 16 divisors (see below), whose sum is σ = 317077376. Its totient is φ = 129711456.

The previous prime is 215801389. The next prime is 215801401. The reversal of 215801391 is 193108512.

It is not a de Polignac number, because 215801391 - 2¹ = 215801389 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 (215841391) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 62665 + ... + 66018.

It is an arithmetic number, because the mean of its divisors is an integer number (19817336).

Almost surely, 2^215801391 is an apocalyptic number.

215801391 is a deficient number, since it is larger than the sum of its proper divisors (101275985).

215801391 is a wasteful number, since it uses less digits than its factorization.

215801391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 128742.

The product of its (nonzero) digits is 2160, while the sum is 30.

The square root of 215801391 is about 14690.1800873917. The cubic root of 215801391 is about 599.8160463853.

The spelling of 215801391 in words is "two hundred fifteen million, eight hundred one thousand, three hundred ninety-one".