20451621 has 8 divisors (see below), whose sum is σ = 27653184. Its totient is φ = 13442240.

The previous prime is 20451601. The next prime is 20451637. The reversal of 20451621 is 12615402.

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

It is a cyclic number.

It is not a de Polignac number, because 20451621 - 2¹⁴ = 20435237 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20451601) 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, 47796 + ... + 48221.

It is an arithmetic number, because the mean of its divisors is an integer number (3456648).

Almost surely, 2^20451621 is an apocalyptic number.

It is an amenable number.

20451621 is a deficient number, since it is larger than the sum of its proper divisors (7201563).

20451621 is an equidigital number, since it uses as much as digits as its factorization.

20451621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96091.

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 20451621 is about 4522.3468464946. The cubic root of 20451621 is about 273.4697195949.

The spelling of 20451621 in words is "twenty million, four hundred fifty-one thousand, six hundred twenty-one".