61621557 has 4 divisors (see below), whose sum is σ = 82162080. Its totient is φ = 41081036.

The previous prime is 61621517. The next prime is 61621589. The reversal of 61621557 is 75512616.

61621557 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 61621557 - 2⁶ = 61621493 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61621507) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10270257 + ... + 10270262.

It is an arithmetic number, because the mean of its divisors is an integer number (20540520).

Almost surely, 2^61621557 is an apocalyptic number.

It is an amenable number.

61621557 is a deficient number, since it is larger than the sum of its proper divisors (20540523).

61621557 is a wasteful number, since it uses less digits than its factorization.

61621557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20540522.

The product of its digits is 12600, while the sum is 33.

The square root of 61621557 is about 7849.9399360759. The cubic root of 61621557 is about 394.9822285440.

The spelling of 61621557 in words is "sixty-one million, six hundred twenty-one thousand, five hundred fifty-seven".