20397621 has 16 divisors (see below), whose sum is σ = 28728000. Its totient is φ = 12837888.

The previous prime is 20397571. The next prime is 20397631. The reversal of 20397621 is 12679302.

It is not a de Polignac number, because 20397621 - 2¹⁴ = 20381237 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20397631) 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, 25195 + ... + 25991.

It is an arithmetic number, because the mean of its divisors is an integer number (1795500).

Almost surely, 2^20397621 is an apocalyptic number.

It is an amenable number.

20397621 is a deficient number, since it is larger than the sum of its proper divisors (8330379).

20397621 is a wasteful number, since it uses less digits than its factorization.

20397621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1268.

The product of its (nonzero) digits is 4536, while the sum is 30.

The square root of 20397621 is about 4516.3725488494. The cubic root of 20397621 is about 273.2288196829.

The spelling of 20397621 in words is "twenty million, three hundred ninety-seven thousand, six hundred twenty-one".