20885621 has 2 divisors, whose sum is σ = 20885622. Its totient is φ = 20885620.

The previous prime is 20885609. The next prime is 20885629. The reversal of 20885621 is 12658802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16728100 + 4157521 = 4090^2 + 2039^2 .

It is a cyclic number.

It is not a de Polignac number, because 20885621 - 2¹⁴ = 20869237 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20885629) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10442810 + 10442811.

It is an arithmetic number, because the mean of its divisors is an integer number (10442811).

Almost surely, 2^20885621 is an apocalyptic number.

It is an amenable number.

20885621 is a deficient number, since it is larger than the sum of its proper divisors (1).

20885621 is an equidigital number, since it uses as much as digits as its factorization.

20885621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7680, while the sum is 32.

The square root of 20885621 is about 4570.0788833455. The cubic root of 20885621 is about 275.3906118518.

The spelling of 20885621 in words is "twenty million, eight hundred eighty-five thousand, six hundred twenty-one".