21626620 has 12 divisors (see below), whose sum is σ = 45415944. Its totient is φ = 8650640.

The previous prime is 21626599. The next prime is 21626621. The reversal of 21626620 is 2662612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21626621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 540646 + ... + 540685.

It is an arithmetic number, because the mean of its divisors is an integer number (3784662).

Almost surely, 2^21626620 is an apocalyptic number.

21626620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21626620 is an abundant number, since it is smaller than the sum of its proper divisors (23789324).

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

21626620 is a wasteful number, since it uses less digits than its factorization.

21626620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1081340 (or 1081338 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 21626620 is about 4650.4429896516. The cubic root of 21626620 is about 278.6096896196.

The spelling of 21626620 in words is "twenty-one million, six hundred twenty-six thousand, six hundred twenty".