20101621 has 2 divisors, whose sum is σ = 20101622. Its totient is φ = 20101620.

The previous prime is 20101607. The next prime is 20101637. The reversal of 20101621 is 12610102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19704721 + 396900 = 4439^2 + 630^2 .

It is a cyclic number.

It is not a de Polignac number, because 20101621 - 2⁵ = 20101589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20101661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10050810 + 10050811.

It is an arithmetic number, because the mean of its divisors is an integer number (10050811).

Almost surely, 2^20101621 is an apocalyptic number.

It is an amenable number.

20101621 is a deficient number, since it is larger than the sum of its proper divisors (1).

20101621 is an equidigital number, since it uses as much as digits as its factorization.

20101621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 20101621 is about 4483.4831325656. The cubic root of 20101621 is about 271.9007215899.

Adding to 20101621 its reverse (12610102), we get a palindrome (32711723).

The spelling of 20101621 in words is "twenty million, one hundred one thousand, six hundred twenty-one".