661272731 has 8 divisors (see below), whose sum is σ = 756157920. Its totient is φ = 566491968.

The previous prime is 661272727. The next prime is 661272743. The reversal of 661272731 is 137272166.

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

It is not a de Polignac number, because 661272731 - 2² = 661272727 is a prime.

It is a super-2 number, since 2×661272731² = 874563249528396722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 661272691 and 661272700.

It is not an unprimeable number, because it can be changed into a prime (661272721) 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, 12026 + ... + 38303.

It is an arithmetic number, because the mean of its divisors is an integer number (94519740).

Almost surely, 2^661272731 is an apocalyptic number.

661272731 is a deficient number, since it is larger than the sum of its proper divisors (94885189).

661272731 is a wasteful number, since it uses less digits than its factorization.

661272731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52213.

The product of its digits is 21168, while the sum is 35.

The square root of 661272731 is about 25715.2237205901. The cubic root of 661272731 is about 871.2180635009.

The spelling of 661272731 in words is "six hundred sixty-one million, two hundred seventy-two thousand, seven hundred thirty-one".