21161028 has 24 divisors (see below), whose sum is σ = 56429632. Its totient is φ = 6045984.

The previous prime is 21161027. The next prime is 21161033. The reversal of 21161028 is 82016112.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a junction number, because it is equal to n+sod(n) for n = 21160995 and 21161013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21161027) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 125875 + ... + 126042.

Almost surely, 2^21161028 is an apocalyptic number.

21161028 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21161028 is an abundant number, since it is smaller than the sum of its proper divisors (35268604).

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

21161028 is a wasteful number, since it uses less digits than its factorization.

21161028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 251931 (or 251929 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 21.

The square root of 21161028 is about 4600.1117377733. Note that the first 3 decimals coincide. The cubic root of 21161028 is about 276.5958038543.

The spelling of 21161028 in words is "twenty-one million, one hundred sixty-one thousand, twenty-eight".