61998731 has 4 divisors (see below), whose sum is σ = 64694352. Its totient is φ = 59303112.

The previous prime is 61998721. The next prime is 61998799. The reversal of 61998731 is 13789916.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 61998731 - 2¹⁰ = 61997707 is a prime.

It is a super-2 number, since 2×61998731² = 7687685291220722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61998701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1347776 + ... + 1347821.

It is an arithmetic number, because the mean of its divisors is an integer number (16173588).

Almost surely, 2^61998731 is an apocalyptic number.

61998731 is a deficient number, since it is larger than the sum of its proper divisors (2695621).

61998731 is a wasteful number, since it uses less digits than its factorization.

61998731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2695620.

The product of its digits is 81648, while the sum is 44.

The square root of 61998731 is about 7873.9272920189. The cubic root of 61998731 is about 395.7864606461.

The spelling of 61998731 in words is "sixty-one million, nine hundred ninety-eight thousand, seven hundred thirty-one".