21522072 has 64 divisors (see below), whose sum is σ = 63221760. Its totient is φ = 6019200.

The previous prime is 21522037. The next prime is 21522073. The reversal of 21522072 is 27022512.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21522073) 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, 297 + ... + 6567.

It is an arithmetic number, because the mean of its divisors is an integer number (987840).

Almost surely, 2^21522072 is an apocalyptic number.

21522072 is a gapful number since it is divisible by the number (22) 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 21522072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31610880).

21522072 is an abundant number, since it is smaller than the sum of its proper divisors (41699688).

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

21522072 is a wasteful number, since it uses less digits than its factorization.

21522072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6304 (or 6300 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 21.

The square root of 21522072 is about 4639.1887221798. The cubic root of 21522072 is about 278.1600100186.

Adding to 21522072 its reverse (27022512), we get a palindrome (48544584).

It can be divided in two parts, 2152 and 2072, that added together give a palindrome (4224).

The spelling of 21522072 in words is "twenty-one million, five hundred twenty-two thousand, seventy-two".