661536723 has 8 divisors (see below), whose sum is σ = 888395200. Its totient is φ = 437851368.

The previous prime is 661536721. The next prime is 661536751. The reversal of 661536723 is 327635166.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 661536723 - 2¹ = 661536721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661536721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 792793 + ... + 793626.

It is an arithmetic number, because the mean of its divisors is an integer number (111049400).

Almost surely, 2^661536723 is an apocalyptic number.

661536723 is a deficient number, since it is larger than the sum of its proper divisors (226858477).

661536723 is a wasteful number, since it uses less digits than its factorization.

661536723 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1586561.

The product of its digits is 136080, while the sum is 39.

The square root of 661536723 is about 25720.3561989332. The cubic root of 661536723 is about 871.3339833975. Note that the first 3 decimals are identical.

The spelling of 661536723 in words is "six hundred sixty-one million, five hundred thirty-six thousand, seven hundred twenty-three".