657442 has 4 divisors (see below), whose sum is σ = 986166. Its totient is φ = 328720.

The previous prime is 657439. The next prime is 657451. The reversal of 657442 is 244756.

657442 is nontrivially palindromic in base 8.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 594441 + 63001 = 771^2 + 251^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 657442.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 164359 + ... + 164362.

2⁶⁵⁷⁴⁴² is an apocalyptic number.

657442 is a deficient number, since it is larger than the sum of its proper divisors (328724).

657442 is a wasteful number, since it uses less digits than its factorization.

657442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328723.

The product of its digits is 6720, while the sum is 28.

The square root of 657442 is about 810.8279718905. The cubic root of 657442 is about 86.9532492029.

Subtracting from 657442 its reverse (244756), we obtain a triangular number (412686 = T₉₀₈).

The spelling of 657442 in words is "six hundred fifty-seven thousand, four hundred forty-two".