20421550405 has 8 divisors (see below), whose sum is σ = 24722727192. Its totient is φ = 16192662528.

The previous prime is 20421550403. The next prime is 20421550427. The reversal of 20421550405 is 50405512402.

It can be written as a sum of positive squares in 4 ways, for example, as 903783969 + 19517766436 = 30063^2 + 139706^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20421550405 - 2¹ = 20421550403 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 (20421550403) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18071604 + ... + 18072733.

It is an arithmetic number, because the mean of its divisors is an integer number (3090340899).

Almost surely, 2^20421550405 is an apocalyptic number.

It is an amenable number.

20421550405 is a deficient number, since it is larger than the sum of its proper divisors (4301176787).

20421550405 is a wasteful number, since it uses less digits than its factorization.

20421550405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36144455.

The product of its (nonzero) digits is 8000, while the sum is 28.

The spelling of 20421550405 in words is "twenty billion, four hundred twenty-one million, five hundred fifty thousand, four hundred five".