21620052 has 18 divisors (see below), whose sum is σ = 54650778. Its totient is φ = 7206672.

The previous prime is 21620021. The next prime is 21620059. The reversal of 21620052 is 25002612.

It can be written as a sum of positive squares in only one way, i.e., 20466576 + 1153476 = 4524^2 + 1074^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21620059) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 300243 + ... + 300314.

Almost surely, 2^21620052 is an apocalyptic number.

It is an amenable number.

21620052 is an abundant number, since it is smaller than the sum of its proper divisors (33030726).

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

21620052 is a wasteful number, since it uses less digits than its factorization.

21620052 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 600567 (or 600562 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21620052 is about 4649.7367667428. The cubic root of 21620052 is about 278.5814821956.

Adding to 21620052 its reverse (25002612), we get a palindrome (46622664).

The spelling of 21620052 in words is "twenty-one million, six hundred twenty thousand, fifty-two".