28979840 has 32 divisors (see below), whose sum is σ = 69281460. Its totient is φ = 11591680.

The previous prime is 28979837. The next prime is 28979851. The reversal of 28979840 is 4897982.

It can be written as a sum of positive squares in 2 ways, for example, as 28472896 + 506944 = 5336^2 + 712^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is a super-2 number, since 2×28979840² = 1679662252851200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22001 + ... + 23280.

Almost surely, 2^28979840 is an apocalyptic number.

28979840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28979840 is an abundant number, since it is smaller than the sum of its proper divisors (40301620).

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

28979840 is an equidigital number, since it uses as much as digits as its factorization.

28979840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45300 (or 45288 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 47.

The square root of 28979840 is about 5383.2926727051. The cubic root of 28979840 is about 307.1604730683.

The spelling of 28979840 in words is "twenty-eight million, nine hundred seventy-nine thousand, eight hundred forty".