28077640 has 32 divisors (see below), whose sum is σ = 63519480. Its totient is φ = 11169792.

The previous prime is 28077601. The next prime is 28077653. The reversal of 28077640 is 4677082.

It can be written as a sum of positive squares in 4 ways, for example, as 10588516 + 17489124 = 3254^2 + 4182^2 .

It is a junction number, because it is equal to n+sod(n) for n = 28077596 and 28077605.

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, 5902 + ... + 9538.

Almost surely, 2^28077640 is an apocalyptic number.

28077640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28077640 is an abundant number, since it is smaller than the sum of its proper divisors (35441840).

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

28077640 is a wasteful number, since it uses less digits than its factorization.

28077640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3841 (or 3837 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 34.

The square root of 28077640 is about 5298.8338339676. The cubic root of 28077640 is about 303.9393057501.

The spelling of 28077640 in words is "twenty-eight million, seventy-seven thousand, six hundred forty".