55172640 has 96 divisors (see below), whose sum is σ = 175271040. Its totient is φ = 14587904.

The previous prime is 55172567. The next prime is 55172651. The reversal of 55172640 is 4627155.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 55172598 and 55172607.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 65341 + ... + 66179.

It is an arithmetic number, because the mean of its divisors is an integer number (1825740).

Almost surely, 2^55172640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 55172640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (87635520).

55172640 is an abundant number, since it is smaller than the sum of its proper divisors (120098400).

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

55172640 is a wasteful number, since it uses less digits than its factorization.

55172640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 994 (or 986 counting only the distinct ones).

The product of its (nonzero) digits is 8400, while the sum is 30.

The square root of 55172640 is about 7427.8287540842. The cubic root of 55172640 is about 380.6927345408.

Adding to 55172640 its reverse (4627155), we get a palindrome (59799795).

The spelling of 55172640 in words is "fifty-five million, one hundred seventy-two thousand, six hundred forty".