21677220 has 60 divisors (see below), whose sum is σ = 68007324. Its totient is φ = 5780160.

The previous prime is 21677213. The next prime is 21677221. The reversal of 21677220 is 2277612.

It can be written as a sum of positive squares in 2 ways, for example, as 4981824 + 16695396 = 2232^2 + 4086^2 .

It is a tau number, because it is divible by the number of its divisors (60).

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

It is not an unprimeable number, because it can be changed into a prime (21677221) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 5071 + ... + 8310.

Almost surely, 2^21677220 is an apocalyptic number.

21677220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21677220 is an abundant number, since it is smaller than the sum of its proper divisors (46330104).

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

21677220 is a wasteful number, since it uses less digits than its factorization.

21677220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13402 (or 13391 counting only the distinct ones).

The product of its (nonzero) digits is 2352, while the sum is 27.

The square root of 21677220 is about 4655.8801530967. The cubic root of 21677220 is about 278.8268089193.

The spelling of 21677220 in words is "twenty-one million, six hundred seventy-seven thousand, two hundred twenty".