55813621 has 4 divisors (see below), whose sum is σ = 58751200. Its totient is φ = 52876044.

The previous prime is 55813619. The next prime is 55813631. The reversal of 55813621 is 12631855.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12631855 = 5 ⋅2526371.

It is a cyclic number.

It is not a de Polignac number, because 55813621 - 2¹ = 55813619 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 (55813631) 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, 1468761 + ... + 1468798.

It is an arithmetic number, because the mean of its divisors is an integer number (14687800).

Almost surely, 2^55813621 is an apocalyptic number.

It is an amenable number.

55813621 is a deficient number, since it is larger than the sum of its proper divisors (2937579).

55813621 is a wasteful number, since it uses less digits than its factorization.

55813621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2937578.

The product of its digits is 7200, while the sum is 31.

The square root of 55813621 is about 7470.8514240346. The cubic root of 55813621 is about 382.1613240925.

The spelling of 55813621 in words is "fifty-five million, eight hundred thirteen thousand, six hundred twenty-one".