55138420 has 24 divisors (see below), whose sum is σ = 115976448. Its totient is φ = 22020000.

The previous prime is 55138411. The next prime is 55138423. The reversal of 55138420 is 2483155.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55138423) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13185 + ... + 16855.

It is an arithmetic number, because the mean of its divisors is an integer number (4832352).

Almost surely, 2^55138420 is an apocalyptic number.

It is an amenable number.

55138420 is an abundant number, since it is smaller than the sum of its proper divisors (60838028).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

55138420 is a wasteful number, since it uses less digits than its factorization.

55138420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4431 (or 4429 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 28.

The square root of 55138420 is about 7425.5248972716. The cubic root of 55138420 is about 380.6140119491.

The spelling of 55138420 in words is "fifty-five million, one hundred thirty-eight thousand, four hundred twenty".