55089721 has 4 divisors (see below), whose sum is σ = 57989200. Its totient is φ = 52190244.

The previous prime is 55089719. The next prime is 55089733. The reversal of 55089721 is 12798055.

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: 12798055 = 5 ⋅2559611.

It is a cyclic number.

It is not a de Polignac number, because 55089721 - 2¹ = 55089719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (55089121) 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, 1449711 + ... + 1449748.

It is an arithmetic number, because the mean of its divisors is an integer number (14497300).

Almost surely, 2^55089721 is an apocalyptic number.

It is an amenable number.

55089721 is a deficient number, since it is larger than the sum of its proper divisors (2899479).

55089721 is a wasteful number, since it uses less digits than its factorization.

55089721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2899478.

The product of its (nonzero) digits is 25200, while the sum is 37.

The square root of 55089721 is about 7422.2450107767. The cubic root of 55089721 is about 380.5019244586.

The spelling of 55089721 in words is "fifty-five million, eighty-nine thousand, seven hundred twenty-one".