21500620 has 48 divisors (see below), whose sum is σ = 46811520. Its totient is φ = 8290304.

The previous prime is 21500593. The next prime is 21500621. The reversal of 21500620 is 2600512.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21500594 and 21500603.

It is not an unprimeable number, because it can be changed into a prime (21500621) 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, 83532 + ... + 83788.

It is an arithmetic number, because the mean of its divisors is an integer number (975240).

Almost surely, 2^21500620 is an apocalyptic number.

21500620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21500620 is an abundant number, since it is smaller than the sum of its proper divisors (25310900).

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

21500620 is a wasteful number, since it uses less digits than its factorization.

21500620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 402 (or 400 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21500620 is about 4636.8761035853. The cubic root of 21500620 is about 278.0675611722.

The spelling of 21500620 in words is "twenty-one million, five hundred thousand, six hundred twenty".