21354942877 has 4 divisors (see below), whose sum is σ = 21366249660. Its totient is φ = 21343636096.

The previous prime is 21354942857. The next prime is 21354942883. The reversal of 21354942877 is 77824945312.

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 17888795001 + 3466147876 = 133749^2 + 58874^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21354942877 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 (21354942827) 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, 5650558 + ... + 5654335.

It is an arithmetic number, because the mean of its divisors is an integer number (5341562415).

Almost surely, 2^21354942877 is an apocalyptic number.

It is an amenable number.

21354942877 is a deficient number, since it is larger than the sum of its proper divisors (11306783).

21354942877 is a wasteful number, since it uses less digits than its factorization.

21354942877 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11306782.

The product of its digits is 3386880, while the sum is 52.

The spelling of 21354942877 in words is "twenty-one billion, three hundred fifty-four million, nine hundred forty-two thousand, eight hundred seventy-seven".