28881385 has 32 divisors (see below), whose sum is σ = 40279680. Its totient is φ = 19688448.

The previous prime is 28881383. The next prime is 28881397. The reversal of 28881385 is 58318882.

28881385 = T₉₁₀ + T₉₁₁ + ... + T₉₇₄.

28881385 = 1² + 2² + ... + 442².

It is not a de Polignac number, because 28881385 - 2¹ = 28881383 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28881383) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 64974 + ... + 65416.

It is an arithmetic number, because the mean of its divisors is an integer number (1258740).

Almost surely, 2^28881385 is an apocalyptic number.

It is an amenable number.

28881385 is a deficient number, since it is larger than the sum of its proper divisors (11398295).

28881385 is a wasteful number, since it uses less digits than its factorization.

28881385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 537.

The product of its digits is 122880, while the sum is 43.

The square root of 28881385 is about 5374.1403963797. The cubic root of 28881385 is about 306.8122333236.

The spelling of 28881385 in words is "twenty-eight million, eight hundred eighty-one thousand, three hundred eighty-five".