21225080 has 32 divisors (see below), whose sum is σ = 49299840. Its totient is φ = 8215680.

The previous prime is 21225077. The next prime is 21225097. The reversal of 21225080 is 8052212.

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

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, 7319 + ... + 9798.

It is an arithmetic number, because the mean of its divisors is an integer number (1540620).

Almost surely, 2^21225080 is an apocalyptic number.

21225080 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21225080 is an abundant number, since it is smaller than the sum of its proper divisors (28074760).

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

21225080 is a wasteful number, since it uses less digits than its factorization.

21225080 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17159 (or 17155 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 20.

The square root of 21225080 is about 4607.0684822347. The cubic root of 21225080 is about 276.8745973222.

Adding to 21225080 its reverse (8052212), we get a palindrome (29277292).

The spelling of 21225080 in words is "twenty-one million, two hundred twenty-five thousand, eighty".