55221031 has 4 divisors (see below), whose sum is σ = 55998864. Its totient is φ = 54443200.

The previous prime is 55221007. The next prime is 55221037. The reversal of 55221031 is 13012255.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13012255 = 5 ⋅2602451.

It is a cyclic number.

It is not a de Polignac number, because 55221031 - 2⁷ = 55220903 is a prime.

It is a super-2 number, since 2×55221031² = 6098724529405922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55221037) 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, 388810 + ... + 388951.

It is an arithmetic number, because the mean of its divisors is an integer number (13999716).

Almost surely, 2^55221031 is an apocalyptic number.

55221031 is a deficient number, since it is larger than the sum of its proper divisors (777833).

55221031 is an equidigital number, since it uses as much as digits as its factorization.

55221031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 777832.

The product of its (nonzero) digits is 300, while the sum is 19.

The square root of 55221031 is about 7431.0854523414. The cubic root of 55221031 is about 380.8040017609.

Adding to 55221031 its reverse (13012255), we get a palindrome (68233286).

The spelling of 55221031 in words is "fifty-five million, two hundred twenty-one thousand, thirty-one".