21450620 has 36 divisors (see below), whose sum is σ = 47557944. Its totient is φ = 8125920.

The previous prime is 21450613. The next prime is 21450623. The reversal of 21450620 is 2605412.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 21450592 and 21450601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21450623) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5735 + ... + 8705.

It is an arithmetic number, because the mean of its divisors is an integer number (1321054).

Almost surely, 2^21450620 is an apocalyptic number.

21450620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21450620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23778972).

21450620 is an abundant number, since it is smaller than the sum of its proper divisors (26107324).

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

21450620 is a wasteful number, since it uses less digits than its factorization.

21450620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3018 (or 2997 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 21450620 is about 4631.4814044752. The cubic root of 21450620 is about 277.8518438346.

The spelling of 21450620 in words is "twenty-one million, four hundred fifty thousand, six hundred twenty".