657671221 has 4 divisors (see below), whose sum is σ = 662691744. Its totient is φ = 652650700.

The previous prime is 657671219. The next prime is 657671233. The reversal of 657671221 is 122176756.

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 657671221 - 2¹ = 657671219 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 (657671281) 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, 2510065 + ... + 2510326.

It is an arithmetic number, because the mean of its divisors is an integer number (165672936).

Almost surely, 2^657671221 is an apocalyptic number.

It is an amenable number.

657671221 is a deficient number, since it is larger than the sum of its proper divisors (5020523).

657671221 is a wasteful number, since it uses less digits than its factorization.

657671221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5020522.

The product of its digits is 35280, while the sum is 37.

The square root of 657671221 is about 25645.1013060974. The cubic root of 657671221 is about 869.6335361507.

The spelling of 657671221 in words is "six hundred fifty-seven million, six hundred seventy-one thousand, two hundred twenty-one".