20285621 has 2 divisors, whose sum is σ = 20285622. Its totient is φ = 20285620.

The previous prime is 20285599. The next prime is 20285627. The reversal of 20285621 is 12658202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18879025 + 1406596 = 4345^2 + 1186^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20285621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20285627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10142810 + 10142811.

It is an arithmetic number, because the mean of its divisors is an integer number (10142811).

Almost surely, 2^20285621 is an apocalyptic number.

It is an amenable number.

20285621 is a deficient number, since it is larger than the sum of its proper divisors (1).

20285621 is an equidigital number, since it uses as much as digits as its factorization.

20285621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 20285621 is about 4503.9561498754. The cubic root of 20285621 is about 272.7278166689.

The spelling of 20285621 in words is "twenty million, two hundred eighty-five thousand, six hundred twenty-one".