28720810 has 8 divisors (see below), whose sum is σ = 51697476. Its totient is φ = 11488320.

The previous prime is 28720801. The next prime is 28720819. The reversal of 28720810 is 1802782.

It is an interprime number because it is at equal distance from previous prime (28720801) and next prime (28720819).

It can be written as a sum of positive squares in 2 ways, for example, as 28206721 + 514089 = 5311^2 + 717^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×28720810² = 1649769854112200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28720819) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1436031 + ... + 1436050.

Almost surely, 2^28720810 is an apocalyptic number.

28720810 is a deficient number, since it is larger than the sum of its proper divisors (22976666).

28720810 is a wasteful number, since it uses less digits than its factorization.

28720810 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2872088.

The product of its (nonzero) digits is 1792, while the sum is 28.

The square root of 28720810 is about 5359.1799745857. The cubic root of 28720810 is about 306.2425704153.

The spelling of 28720810 in words is "twenty-eight million, seven hundred twenty thousand, eight hundred ten".