20461621 has 4 divisors (see below), whose sum is σ = 20479500. Its totient is φ = 20443744.

The previous prime is 20461619. The next prime is 20461631. The reversal of 20461621 is 12616402.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18584721 + 1876900 = 4311^2 + 1370^2 .

It is a cyclic number.

It is not a de Polignac number, because 20461621 - 2¹ = 20461619 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20461592 and 20461601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20461631) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7096 + ... + 9553.

It is an arithmetic number, because the mean of its divisors is an integer number (5119875).

Almost surely, 2^20461621 is an apocalyptic number.

It is an amenable number.

20461621 is a deficient number, since it is larger than the sum of its proper divisors (17879).

20461621 is a wasteful number, since it uses less digits than its factorization.

20461621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17878.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 20461621 is about 4523.4523320137. The cubic root of 20461621 is about 273.5142841407.

The spelling of 20461621 in words is "twenty million, four hundred sixty-one thousand, six hundred twenty-one".