28121607 has 16 divisors (see below), whose sum is σ = 41743360. Its totient is φ = 18711000.

The previous prime is 28121603. The next prime is 28121629. The reversal of 28121607 is 70612182.

It is not a de Polignac number, because 28121607 - 2² = 28121603 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28121603) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26232 + ... + 27282.

It is an arithmetic number, because the mean of its divisors is an integer number (2608960).

Almost surely, 2^28121607 is an apocalyptic number.

28121607 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

28121607 is a deficient number, since it is larger than the sum of its proper divisors (13621753).

28121607 is a wasteful number, since it uses less digits than its factorization.

28121607 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2051 (or 2045 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 28121607 is about 5302.9809541427. The cubic root of 28121607 is about 304.0978700060.

Adding to 28121607 its reverse (70612182), we get a palindrome (98733789).

The spelling of 28121607 in words is "twenty-eight million, one hundred twenty-one thousand, six hundred seven".