661355457 has 16 divisors (see below), whose sum is σ = 1040289792. Its totient is φ = 365726160.

The previous prime is 661355449. The next prime is 661355503. The reversal of 661355457 is 754553166.

It is not a de Polignac number, because 661355457 - 2³ = 661355449 is a prime.

It is not an unprimeable number, because it can be changed into a prime (661355257) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 507303 + ... + 508604.

It is an arithmetic number, because the mean of its divisors is an integer number (65018112).

Almost surely, 2^661355457 is an apocalyptic number.

It is an amenable number.

661355457 is a deficient number, since it is larger than the sum of its proper divisors (378934335).

661355457 is a wasteful number, since it uses less digits than its factorization.

661355457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1015948.

The product of its digits is 378000, while the sum is 42.

The square root of 661355457 is about 25716.8321727230. The cubic root of 661355457 is about 871.2543921224.

The spelling of 661355457 in words is "six hundred sixty-one million, three hundred fifty-five thousand, four hundred fifty-seven".