21144919477 has 4 divisors (see below), whose sum is σ = 23067184896. Its totient is φ = 19222654060.

The previous prime is 21144919421. The next prime is 21144919489. The reversal of 21144919477 is 77491944112.

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 21144919477 - 2²⁷ = 21010701749 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21144919477.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21144919777) 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, 961132693 + ... + 961132714.

It is an arithmetic number, because the mean of its divisors is an integer number (5766796224).

Almost surely, 2^21144919477 is an apocalyptic number.

It is an amenable number.

21144919477 is a deficient number, since it is larger than the sum of its proper divisors (1922265419).

21144919477 is a wasteful number, since it uses less digits than its factorization.

21144919477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1922265418.

The product of its digits is 508032, while the sum is 49.

The spelling of 21144919477 in words is "twenty-one billion, one hundred forty-four million, nine hundred nineteen thousand, four hundred seventy-seven".