61665731 has 4 divisors (see below), whose sum is σ = 61885464. Its totient is φ = 61446000.

The previous prime is 61665719. The next prime is 61665733. The reversal of 61665731 is 13756616.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61665731 is a prime.

It is a super-2 number, since 2×61665731² = 7605324759528722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 61665691 and 61665700.

It is not an unprimeable number, because it can be changed into a prime (61665733) 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, 109445 + ... + 110006.

It is an arithmetic number, because the mean of its divisors is an integer number (15471366).

Almost surely, 2^61665731 is an apocalyptic number.

61665731 is a deficient number, since it is larger than the sum of its proper divisors (219733).

61665731 is a wasteful number, since it uses less digits than its factorization.

61665731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 219732.

The product of its digits is 22680, while the sum is 35.

The square root of 61665731 is about 7852.7530841101. The cubic root of 61665731 is about 395.0765882575.

The spelling of 61665731 in words is "sixty-one million, six hundred sixty-five thousand, seven hundred thirty-one".