211891457 has 4 divisors (see below), whose sum is σ = 212186880. Its totient is φ = 211596036.

The previous prime is 211891441. The next prime is 211891481. The reversal of 211891457 is 754198112.

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 211891457 - 2⁴ = 211891441 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 211891457.

It is not an unprimeable number, because it can be changed into a prime (211891357) 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, 146633 + ... + 148070.

It is an arithmetic number, because the mean of its divisors is an integer number (53046720).

Almost surely, 2^211891457 is an apocalyptic number.

It is an amenable number.

211891457 is a deficient number, since it is larger than the sum of its proper divisors (295423).

211891457 is an equidigital number, since it uses as much as digits as its factorization.

211891457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 295422.

The product of its digits is 20160, while the sum is 38.

The square root of 211891457 is about 14556.4919194152. The cubic root of 211891457 is about 596.1714153808.

The spelling of 211891457 in words is "two hundred eleven million, eight hundred ninety-one thousand, four hundred fifty-seven".