28720826 has 4 divisors (see below), whose sum is σ = 43081242. Its totient is φ = 14360412.

The previous prime is 28720819. The next prime is 28720831. The reversal of 28720826 is 62802782.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 15405625 + 13315201 = 3925^2 + 3649^2 .

It is a super-2 number, since 2×28720826² = 1649771692244552, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7180205 + ... + 7180208.

Almost surely, 2^28720826 is an apocalyptic number.

28720826 is a deficient number, since it is larger than the sum of its proper divisors (14360416).

28720826 is a wasteful number, since it uses less digits than its factorization.

28720826 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14360415.

The product of its (nonzero) digits is 21504, while the sum is 35.

The square root of 28720826 is about 5359.1814673511. The cubic root of 28720826 is about 306.2426272833.

The spelling of 28720826 in words is "twenty-eight million, seven hundred twenty thousand, eight hundred twenty-six".