612561555421 has 4 divisors (see below), whose sum is σ = 613385999712. Its totient is φ = 611737111132.

The previous prime is 612561555413. The next prime is 612561555443. The reversal of 612561555421 is 124555165216.

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 612561555421 - 2³ = 612561555413 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 (612561555451) 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, 412221031 + ... + 412222516.

It is an arithmetic number, because the mean of its divisors is an integer number (153346499928).

Almost surely, 2^612561555421 is an apocalyptic number.

It is an amenable number.

612561555421 is a deficient number, since it is larger than the sum of its proper divisors (824444291).

612561555421 is an equidigital number, since it uses as much as digits as its factorization.

612561555421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 824444290.

The product of its digits is 360000, while the sum is 43.

The spelling of 612561555421 in words is "six hundred twelve billion, five hundred sixty-one million, five hundred fifty-five thousand, four hundred twenty-one".