28391970 has 32 divisors (see below), whose sum is σ = 70341120. Its totient is φ = 7326720.

The previous prime is 28391953. The next prime is 28391971. The reversal of 28391970 is 7919382.

It is a super-2 number, since 2×28391970² = 1612207920961800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (28391971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14335 + ... + 16194.

It is an arithmetic number, because the mean of its divisors is an integer number (2198160).

Almost surely, 2^28391970 is an apocalyptic number.

28391970 is an abundant number, since it is smaller than the sum of its proper divisors (41949150).

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

28391970 is a wasteful number, since it uses less digits than its factorization.

28391970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30570.

The product of its (nonzero) digits is 27216, while the sum is 39.

The square root of 28391970 is about 5328.4115832019. The cubic root of 28391970 is about 305.0693025354.

The spelling of 28391970 in words is "twenty-eight million, three hundred ninety-one thousand, nine hundred seventy".