61520557 has 4 divisors (see below), whose sum is σ = 70309216. Its totient is φ = 52731900.

The previous prime is 61520549. The next prime is 61520579. The reversal of 61520557 is 75502516.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 61520557 - 2³ = 61520549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61520597) 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, 4394319 + ... + 4394332.

It is an arithmetic number, because the mean of its divisors is an integer number (17577304).

Almost surely, 2^61520557 is an apocalyptic number.

It is an amenable number.

61520557 is a deficient number, since it is larger than the sum of its proper divisors (8788659).

61520557 is an equidigital number, since it uses as much as digits as its factorization.

61520557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8788658.

The product of its (nonzero) digits is 10500, while the sum is 31.

The square root of 61520557 is about 7843.5041276205. The cubic root of 61520557 is about 394.7663137334.

The spelling of 61520557 in words is "sixty-one million, five hundred twenty thousand, five hundred fifty-seven".