28172640 has 48 divisors (see below), whose sum is σ = 88745328. Its totient is φ = 7512576.

The previous prime is 28172633. The next prime is 28172657. The reversal of 28172640 is 4627182.

It is a tau number, because it is divible by the number of its divisors (48).

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 = 28172598 and 28172607.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28867 + ... + 29826.

It is an arithmetic number, because the mean of its divisors is an integer number (1848861).

Almost surely, 2^28172640 is an apocalyptic number.

28172640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28172640 is an abundant number, since it is smaller than the sum of its proper divisors (60572688).

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

28172640 is a wasteful number, since it uses less digits than its factorization.

28172640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58711 (or 58703 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 30.

The square root of 28172640 is about 5307.7905007639. The cubic root of 28172640 is about 304.2817102404.

The spelling of 28172640 in words is "twenty-eight million, one hundred seventy-two thousand, six hundred forty".