891157213 has 4 divisors (see below), whose sum is σ = 894445888. Its totient is φ = 887868540.

The previous prime is 891157207. The next prime is 891157231. The reversal of 891157213 is 312751198.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 891157213 - 2⁹ = 891156701 is a prime.

It is a super-2 number, since 2×891157213² = 1588322356563854738, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (891107213) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1643931 + ... + 1644472.

It is an arithmetic number, because the mean of its divisors is an integer number (223611472).

Almost surely, 2^891157213 is an apocalyptic number.

It is an amenable number.

891157213 is a deficient number, since it is larger than the sum of its proper divisors (3288675).

891157213 is a wasteful number, since it uses less digits than its factorization.

891157213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3288674.

The product of its digits is 15120, while the sum is 37.

The square root of 891157213 is about 29852.2564138793. The cubic root of 891157213 is about 962.3168911917.

The spelling of 891157213 in words is "eight hundred ninety-one million, one hundred fifty-seven thousand, two hundred thirteen".