55139397 has 4 divisors (see below), whose sum is σ = 73519200. Its totient is φ = 36759596.

The previous prime is 55139369. The next prime is 55139401. The reversal of 55139397 is 79393155.

It is a happy number.

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 55139397 - 2⁶ = 55139333 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55139597) 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, 9189897 + ... + 9189902.

It is an arithmetic number, because the mean of its divisors is an integer number (18379800).

Almost surely, 2^55139397 is an apocalyptic number.

It is an amenable number.

55139397 is a deficient number, since it is larger than the sum of its proper divisors (18379803).

55139397 is a wasteful number, since it uses less digits than its factorization.

55139397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18379802.

The product of its digits is 127575, while the sum is 42.

The square root of 55139397 is about 7425.5906835753. The cubic root of 55139397 is about 380.6162599744.

The spelling of 55139397 in words is "fifty-five million, one hundred thirty-nine thousand, three hundred ninety-seven".