61991577 has 6 divisors (see below), whose sum is σ = 89543402. Its totient is φ = 41327712.

The previous prime is 61991563. The next prime is 61991597. The reversal of 61991577 is 77519916.

It can be written as a sum of positive squares in only one way, i.e., 57927321 + 4064256 = 7611^2 + 2016^2 .

It is not a de Polignac number, because 61991577 - 2⁴ = 61991561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61991507) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3443968 + ... + 3443985.

Almost surely, 2^61991577 is an apocalyptic number.

It is an amenable number.

61991577 is a deficient number, since it is larger than the sum of its proper divisors (27551825).

61991577 is a wasteful number, since it uses less digits than its factorization.

61991577 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6887959 (or 6887956 counting only the distinct ones).

The product of its digits is 119070, while the sum is 45.

The square root of 61991577 is about 7873.4729948099. The cubic root of 61991577 is about 395.7712368654.

It can be divided in two parts, 6199 and 1577, that added together give a 5-th power (7776 = 6⁵).

The spelling of 61991577 in words is "sixty-one million, nine hundred ninety-one thousand, five hundred seventy-seven".