55724021 has 4 divisors (see below), whose sum is σ = 55756992. Its totient is φ = 55691052.

The previous prime is 55723973. The next prime is 55724027. The reversal of 55724021 is 12042755.

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 55724021 - 2²² = 51529717 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 (55724027) 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, 13805 + ... + 17378.

It is an arithmetic number, because the mean of its divisors is an integer number (13939248).

Almost surely, 2^55724021 is an apocalyptic number.

It is an amenable number.

55724021 is a deficient number, since it is larger than the sum of its proper divisors (32971).

55724021 is a wasteful number, since it uses less digits than its factorization.

55724021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32970.

The product of its (nonzero) digits is 2800, while the sum is 26.

The square root of 55724021 is about 7464.8523763032. The cubic root of 55724021 is about 381.9567145749.

Adding to 55724021 its reverse (12042755), we get a palindrome (67766776).

The spelling of 55724021 in words is "fifty-five million, seven hundred twenty-four thousand, twenty-one".