21628180 has 24 divisors (see below), whose sum is σ = 51907968. Its totient is φ = 7415328.

The previous prime is 21628169. The next prime is 21628193. The reversal of 21628180 is 8182612.

It is a super-2 number, since 2×21628180² = 935556340224800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 77104 + ... + 77383.

It is an arithmetic number, because the mean of its divisors is an integer number (2162832).

Almost surely, 2^21628180 is an apocalyptic number.

21628180 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21628180 is an abundant number, since it is smaller than the sum of its proper divisors (30279788).

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

21628180 is a wasteful number, since it uses less digits than its factorization.

21628180 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154503 (or 154501 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 28.

The square root of 21628180 is about 4650.6107125839. The cubic root of 21628180 is about 278.6163884730.

The spelling of 21628180 in words is "twenty-one million, six hundred twenty-eight thousand, one hundred eighty".