61597731 has 8 divisors (see below), whose sum is σ = 88448080. Its totient is φ = 37906272.

The previous prime is 61597727. The next prime is 61597741. The reversal of 61597731 is 13779516.

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

It is not a de Polignac number, because 61597731 - 2² = 61597727 is a prime.

It is a super-2 number, since 2×61597731² = 7588560928696722, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39), and also a Moran number because the ratio is a prime number: 1579429 = 61597731 / (6 + 1 + 5 + 9 + 7 + 7 + 3 + 1).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 61597731.

It is not an unprimeable number, because it can be changed into a prime (61597741) 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, 789676 + ... + 789753.

It is an arithmetic number, because the mean of its divisors is an integer number (11056010).

Almost surely, 2^61597731 is an apocalyptic number.

61597731 is a deficient number, since it is larger than the sum of its proper divisors (26850349).

61597731 is a wasteful number, since it uses less digits than its factorization.

61597731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1579445.

The product of its digits is 39690, while the sum is 39.

The square root of 61597731 is about 7848.4221981236. The cubic root of 61597731 is about 394.9313153020.

It can be divided in two parts, 615 and 97731, that added together give a triangular number (98346 = T₄₄₃).

The spelling of 61597731 in words is "sixty-one million, five hundred ninety-seven thousand, seven hundred thirty-one".