661456377 has 24 divisors (see below), whose sum is σ = 987225408. Its totient is φ = 426535200.

The previous prime is 661456357. The next prime is 661456409. The reversal of 661456377 is 773654166.

661456377 is a `hidden beast` number, since 6 + 6 + 1 + 4 + 5 + 637 + 7 = 666.

It is not a de Polignac number, because 661456377 - 2⁷ = 661456249 is a prime.

It is a super-2 number, since 2×661456377² = 875049077347932258, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (661456307) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24102 + ... + 43632.

It is an arithmetic number, because the mean of its divisors is an integer number (41134392).

Almost surely, 2^661456377 is an apocalyptic number.

It is an amenable number.

661456377 is a deficient number, since it is larger than the sum of its proper divisors (325769031).

661456377 is a wasteful number, since it uses less digits than its factorization.

661456377 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19661 (or 19658 counting only the distinct ones).

The product of its digits is 635040, while the sum is 45.

The square root of 661456377 is about 25718.7942369000. The cubic root of 661456377 is about 871.2987064268.

The spelling of 661456377 in words is "six hundred sixty-one million, four hundred fifty-six thousand, three hundred seventy-seven".