661597623 has 6 divisors (see below), whose sum is σ = 955641024. Its totient is φ = 441065076.

The previous prime is 661597583. The next prime is 661597633. The reversal of 661597623 is 326795166.

661597623 is a `hidden beast` number, since 6 + 6 + 15 + 9 + 7 + 623 = 666.

It is not a de Polignac number, because 661597623 - 2²⁵ = 628043191 is a prime.

It is a super-2 number, since 2×661597623² = 875422829518500258, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661597633) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 36755415 + ... + 36755432.

It is an arithmetic number, because the mean of its divisors is an integer number (159273504).

Almost surely, 2^661597623 is an apocalyptic number.

661597623 is a deficient number, since it is larger than the sum of its proper divisors (294043401).

661597623 is a wasteful number, since it uses less digits than its factorization.

661597623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73510853 (or 73510850 counting only the distinct ones).

The product of its digits is 408240, while the sum is 45.

The square root of 661597623 is about 25721.5400588689. The cubic root of 661597623 is about 871.3607204424.

The spelling of 661597623 in words is "six hundred sixty-one million, five hundred ninety-seven thousand, six hundred twenty-three".