661457 has 4 divisors (see below), whose sum is σ = 690240. Its totient is φ = 632676.

The previous prime is 661439. The next prime is 661459. The reversal of 661457 is 754166.

661457 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 661457 - 2⁶ = 661393 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 (661459) 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, 14357 + ... + 14402.

It is an arithmetic number, because the mean of its divisors is an integer number (172560).

2⁶⁶¹⁴⁵⁷ is an apocalyptic number.

It is an amenable number.

661457 is a deficient number, since it is larger than the sum of its proper divisors (28783).

661457 is a wasteful number, since it uses less digits than its factorization.

661457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28782.

The product of its digits is 5040, while the sum is 29.

The square root of 661457 is about 813.3000676257. The cubic root of 661457 is about 87.1298979974.

The spelling of 661457 in words is "six hundred sixty-one thousand, four hundred fifty-seven".