61815986 has 4 divisors (see below), whose sum is σ = 92723982. Its totient is φ = 30907992.

The previous prime is 61815977. The next prime is 61815991. The reversal of 61815986 is 68951816.

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

It can be written as a sum of positive squares in only one way, i.e., 51051025 + 10764961 = 7145^2 + 3281^2 .

It is a super-2 number, since 2×61815986² = 7642432250304392, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15453995 + ... + 15453998.

Almost surely, 2^61815986 is an apocalyptic number.

61815986 is a deficient number, since it is larger than the sum of its proper divisors (30907996).

61815986 is a wasteful number, since it uses less digits than its factorization.

61815986 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30907995.

The product of its digits is 103680, while the sum is 44.

The square root of 61815986 is about 7862.3142903346. The cubic root of 61815986 is about 395.3972097916.

It can be divided in two parts, 6181 and 5986, that added together give a cube (12167 = 23³).

The spelling of 61815986 in words is "sixty-one million, eight hundred fifteen thousand, nine hundred eighty-six".