661654137730 has 32 divisors (see below), whose sum is σ = 1192479323760. Its totient is φ = 264328120320.

The previous prime is 661654137719. The next prime is 661654137737. The reversal of 661654137730 is 37731456166.

It can be written as a sum of positive squares in 8 ways, for example, as 152419187281 + 509234950449 = 390409^2 + 713607^2 .

It is not an unprimeable number, because it can be changed into a prime (661654137737) 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, 28147342 + ... + 28170838.

Almost surely, 2^661654137730 is an apocalyptic number.

661654137730 is a deficient number, since it is larger than the sum of its proper divisors (530825186030).

661654137730 is a wasteful number, since it uses less digits than its factorization.

661654137730 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26934.

The product of its (nonzero) digits is 1905120, while the sum is 49.

The spelling of 661654137730 in words is "six hundred sixty-one billion, six hundred fifty-four million, one hundred thirty-seven thousand, seven hundred thirty".