215748891 has 12 divisors (see below), whose sum is σ = 311840568. Its totient is φ = 143738784.

The previous prime is 215748889. The next prime is 215748917. The reversal of 215748891 is 198847512.

It is not a de Polignac number, because 215748891 - 2¹ = 215748889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (215748811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8551 + ... + 22463.

It is an arithmetic number, because the mean of its divisors is an integer number (25986714).

Almost surely, 2^215748891 is an apocalyptic number.

215748891 is a deficient number, since it is larger than the sum of its proper divisors (96091677).

215748891 is a wasteful number, since it uses less digits than its factorization.

215748891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15642 (or 15639 counting only the distinct ones).

The product of its digits is 161280, while the sum is 45.

The square root of 215748891 is about 14688.3930707208. The cubic root of 215748891 is about 599.7674015082.

The spelling of 215748891 in words is "two hundred fifteen million, seven hundred forty-eight thousand, eight hundred ninety-one".