21405467477 has 4 divisors (see below), whose sum is σ = 22336140000. Its totient is φ = 20474794956.

The previous prime is 21405467441. The next prime is 21405467557. The reversal of 21405467477 is 77476450412.

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 a cyclic number.

It is not a de Polignac number, because 21405467477 - 2³⁰ = 20331725653 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 (21405467077) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 465336227 + ... + 465336272.

It is an arithmetic number, because the mean of its divisors is an integer number (5584035000).

Almost surely, 2^21405467477 is an apocalyptic number.

It is an amenable number.

21405467477 is a deficient number, since it is larger than the sum of its proper divisors (930672523).

21405467477 is an equidigital number, since it uses as much as digits as its factorization.

21405467477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 930672522.

The product of its (nonzero) digits is 1317120, while the sum is 47.

The spelling of 21405467477 in words is "twenty-one billion, four hundred five million, four hundred sixty-seven thousand, four hundred seventy-seven".