21520122 has 48 divisors (see below), whose sum is σ = 49102560. Its totient is φ = 6267456.

The previous prime is 21520091. The next prime is 21520133. The reversal of 21520122 is 22102512.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18708 + ... + 19824.

It is an arithmetic number, because the mean of its divisors is an integer number (1022970).

Almost surely, 2^21520122 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21520122, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24551280).

21520122 is an abundant number, since it is smaller than the sum of its proper divisors (27582438).

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

21520122 is a wasteful number, since it uses less digits than its factorization.

21520122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1167 (or 1154 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 21520122 is about 4638.9785513624. The cubic root of 21520122 is about 278.1516089005.

Adding to 21520122 its reverse (22102512), we get a palindrome (43622634).

The spelling of 21520122 in words is "twenty-one million, five hundred twenty thousand, one hundred twenty-two".