20550747421 has 4 divisors (see below), whose sum is σ = 20664287644. Its totient is φ = 20437207200.

The previous prime is 20550747409. The next prime is 20550747431. The reversal of 20550747421 is 12474705502.

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 3023900100 + 17526847321 = 54990^2 + 132389^2 .

It is a cyclic number.

It is not a de Polignac number, because 20550747421 - 2²³ = 20542358813 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 (20550747431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 56769840 + ... + 56770201.

It is an arithmetic number, because the mean of its divisors is an integer number (5166071911).

Almost surely, 2^20550747421 is an apocalyptic number.

It is an amenable number.

20550747421 is a deficient number, since it is larger than the sum of its proper divisors (113540223).

20550747421 is a wasteful number, since it uses less digits than its factorization.

20550747421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113540222.

The product of its (nonzero) digits is 78400, while the sum is 37.

The spelling of 20550747421 in words is "twenty billion, five hundred fifty million, seven hundred forty-seven thousand, four hundred twenty-one".