28138550 has 36 divisors (see below), whose sum is σ = 57540588. Its totient is φ = 10230000.

The previous prime is 28138549. The next prime is 28138573. The reversal of 28138550 is 5583182.

It is a happy number.

It is a super-2 number, since 2×28138550² = 1583555992205000, which contains 22 as substring.

It is a Smith number, since the sum of its digits (32) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 3725 + ... + 8375.

Almost surely, 2^28138550 is an apocalyptic number.

28138550 is an abundant number, since it is smaller than the sum of its proper divisors (29402038).

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

28138550 is a wasteful number, since it uses less digits than its factorization.

28138550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4685 (or 4669 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 32.

The square root of 28138550 is about 5304.5782113190. The cubic root of 28138550 is about 304.1589297671.

The spelling of 28138550 in words is "twenty-eight million, one hundred thirty-eight thousand, five hundred fifty".