101809621 has 2 divisors, whose sum is σ = 101809622. Its totient is φ = 101809620.

The previous prime is 101809579. The next prime is 101809627. The reversal of 101809621 is 126908101.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 101808100 + 1521 = 10090^2 + 39^2 .

It is a cyclic number.

It is not a de Polignac number, because 101809621 - 2⁷ = 101809493 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 101809621.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (101809627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50904810 + 50904811.

It is an arithmetic number, because the mean of its divisors is an integer number (50904811).

Almost surely, 2^101809621 is an apocalyptic number.

It is an amenable number.

101809621 is a deficient number, since it is larger than the sum of its proper divisors (1).

101809621 is an equidigital number, since it uses as much as digits as its factorization.

101809621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 28.

The square root of 101809621 is about 10090.0753713736. The cubic root of 101809621 is about 466.9420011821.

The spelling of 101809621 in words is "one hundred one million, eight hundred nine thousand, six hundred twenty-one".