21731457477 has 4 divisors (see below), whose sum is σ = 28975276640. Its totient is φ = 14487638316.

The previous prime is 21731457457. The next prime is 21731457491. The reversal of 21731457477 is 77475413712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21731457477 - 2⁶ = 21731457413 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 (21731457457) 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, 3621909577 + ... + 3621909582.

It is an arithmetic number, because the mean of its divisors is an integer number (7243819160).

Almost surely, 2^21731457477 is an apocalyptic number.

It is an amenable number.

21731457477 is a deficient number, since it is larger than the sum of its proper divisors (7243819163).

21731457477 is an equidigital number, since it uses as much as digits as its factorization.

21731457477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7243819162.

The product of its digits is 1152480, while the sum is 48.

The spelling of 21731457477 in words is "twenty-one billion, seven hundred thirty-one million, four hundred fifty-seven thousand, four hundred seventy-seven".