21620265 has 8 divisors (see below), whose sum is σ = 34592448. Its totient is φ = 11530800.

The previous prime is 21620251. The next prime is 21620267. The reversal of 21620265 is 56202612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21620265 - 2¹² = 21616169 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21620267) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 720661 + ... + 720690.

It is an arithmetic number, because the mean of its divisors is an integer number (4324056).

Almost surely, 2^21620265 is an apocalyptic number.

It is an amenable number.

21620265 is a deficient number, since it is larger than the sum of its proper divisors (12972183).

21620265 is a wasteful number, since it uses less digits than its factorization.

21620265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1441359.

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 21620265 is about 4649.7596712088. The cubic root of 21620265 is about 278.5823970510.

Adding to 21620265 its reverse (56202612), we get a palindrome (77822877).

The spelling of 21620265 in words is "twenty-one million, six hundred twenty thousand, two hundred sixty-five".