661156460643734 has 64 divisors (see below), whose sum is σ = 1127207673849600. Its totient is φ = 288189714393600.

The previous prime is 661156460643719. The next prime is 661156460643751. The reversal of 661156460643734 is 437346064651166.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 420009122 + ... + 421580330.

It is an arithmetic number, because the mean of its divisors is an integer number (17612619903900).

Almost surely, 2^{661156460643734} is an apocalyptic number.

661156460643734 is a deficient number, since it is larger than the sum of its proper divisors (466051213205866).

661156460643734 is a wasteful number, since it uses less digits than its factorization.

661156460643734 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1579229.

The product of its (nonzero) digits is 156764160, while the sum is 62.

The spelling of 661156460643734 in words is "six hundred sixty-one trillion, one hundred fifty-six billion, four hundred sixty million, six hundred forty-three thousand, seven hundred thirty-four".