20624940421 has 4 divisors (see below), whose sum is σ = 20625228844. Its totient is φ = 20624652000.

The previous prime is 20624940419. The next prime is 20624940437. The reversal of 20624940421 is 12404942602.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 15621500196 + 5003440225 = 124986^2 + 70735^2 .

It is a 3-Lehmer number, since φ(20624940421) divides (20624940421-1)³.

It is a cyclic number.

It is not a de Polignac number, because 20624940421 - 2¹ = 20624940419 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20624940221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52441 + ... + 209761.

It is an arithmetic number, because the mean of its divisors is an integer number (5156307211).

It is a Poulet number, since it divides 2^20624940420-1.

Almost surely, 2^20624940421 is an apocalyptic number.

20624940421 is the 82916-th hex number.

It is an amenable number.

20624940421 is a deficient number, since it is larger than the sum of its proper divisors (288423).

20624940421 is a wasteful number, since it uses less digits than its factorization.

20624940421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 288422.

The product of its (nonzero) digits is 27648, while the sum is 34.

The spelling of 20624940421 in words is "twenty billion, six hundred twenty-four million, nine hundred forty thousand, four hundred twenty-one".