20475457421 has 2 divisors, whose sum is σ = 20475457422. Its totient is φ = 20475457420.

The previous prime is 20475457399. The next prime is 20475457423. The reversal of 20475457421 is 12475457402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17393653225 + 3081804196 = 131885^2 + 55514^2 .

It is a cyclic number.

It is not a de Polignac number, because 20475457421 - 2¹⁸ = 20475195277 is a prime.

Together with 20475457423, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20475457423) 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 as a sum of consecutive naturals, namely, 10237728710 + 10237728711.

It is an arithmetic number, because the mean of its divisors is an integer number (10237728711).

Almost surely, 2^20475457421 is an apocalyptic number.

It is an amenable number.

20475457421 is a deficient number, since it is larger than the sum of its proper divisors (1).

20475457421 is an equidigital number, since it uses as much as digits as its factorization.

20475457421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 313600, while the sum is 41.

The spelling of 20475457421 in words is "twenty billion, four hundred seventy-five million, four hundred fifty-seven thousand, four hundred twenty-one".