661374553 has 32 divisors (see below), whose sum is σ = 839024640. Its totient is φ = 508524480.

The previous prime is 661374541. The next prime is 661374587. The reversal of 661374553 is 355473166.

It is a cyclic number.

It is not a de Polignac number, because 661374553 - 2¹⁷ = 661243481 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661374533) 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 31 ways as a sum of consecutive naturals, for example, 192075 + ... + 195487.

It is an arithmetic number, because the mean of its divisors is an integer number (26219520).

Almost surely, 2^661374553 is an apocalyptic number.

It is an amenable number.

661374553 is a deficient number, since it is larger than the sum of its proper divisors (177650087).

661374553 is a wasteful number, since it uses less digits than its factorization.

661374553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3517.

The product of its digits is 226800, while the sum is 40.

The square root of 661374553 is about 25717.2034443872. The cubic root of 661374553 is about 871.2627775847.

The spelling of 661374553 in words is "six hundred sixty-one million, three hundred seventy-four thousand, five hundred fifty-three".