21400909877 has 8 divisors (see below), whose sum is σ = 21852434136. Its totient is φ = 20953665792.

The previous prime is 21400909841. The next prime is 21400909883. The reversal of 21400909877 is 77890900412.

It can be written as a sum of positive squares in 4 ways, for example, as 8135859601 + 13265050276 = 90199^2 + 115174^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21400909877 - 2¹⁸ = 21400647733 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 (21400009877) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1059938 + ... + 1079939.

It is an arithmetic number, because the mean of its divisors is an integer number (2731554267).

Almost surely, 2^21400909877 is an apocalyptic number.

It is an amenable number.

21400909877 is a deficient number, since it is larger than the sum of its proper divisors (451524259).

21400909877 is a wasteful number, since it uses less digits than its factorization.

21400909877 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2140087.

The product of its (nonzero) digits is 254016, while the sum is 47.

The spelling of 21400909877 in words is "twenty-one billion, four hundred million, nine hundred nine thousand, eight hundred seventy-seven".