55399631 has 4 divisors (see below), whose sum is σ = 63313872. Its totient is φ = 47485392.

The previous prime is 55399601. The next prime is 55399637. The reversal of 55399631 is 13699355.

55399631 = T₃₉₇₅ + T₃₉₇₆ + ... + T₃₉₈₁.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13699355 = 5 ⋅2739871.

It is a cyclic number.

It is not a de Polignac number, because 55399631 - 2¹⁴ = 55383247 is a prime.

It is a super-2 number, since 2×55399631² = 6138238229872322, 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 (55399637) 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, 3957110 + ... + 3957123.

It is an arithmetic number, because the mean of its divisors is an integer number (15828468).

Almost surely, 2^55399631 is an apocalyptic number.

55399631 is a deficient number, since it is larger than the sum of its proper divisors (7914241).

55399631 is an equidigital number, since it uses as much as digits as its factorization.

55399631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7914240.

The product of its digits is 109350, while the sum is 41.

The square root of 55399631 is about 7443.0928383300. The cubic root of 55399631 is about 381.2141015738.

The spelling of 55399631 in words is "fifty-five million, three hundred ninety-nine thousand, six hundred thirty-one".