21403709977 has 4 divisors (see below), whose sum is σ = 23050149220. Its totient is φ = 19757270736.

The previous prime is 21403709963. The next prime is 21403709983. The reversal of 21403709977 is 77990730412.

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 3830495881 + 17573214096 = 61891^2 + 132564^2 .

It is a cyclic number.

It is not a de Polignac number, because 21403709977 - 2¹⁵ = 21403677209 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 21403709977.

It is not an unprimeable number, because it can be changed into a prime (21403709077) 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, 823219602 + ... + 823219627.

It is an arithmetic number, because the mean of its divisors is an integer number (5762537305).

Almost surely, 2^21403709977 is an apocalyptic number.

It is an amenable number.

21403709977 is a deficient number, since it is larger than the sum of its proper divisors (1646439243).

21403709977 is a wasteful number, since it uses less digits than its factorization.

21403709977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1646439242.

The product of its (nonzero) digits is 666792, while the sum is 49.

The spelling of 21403709977 in words is "twenty-one billion, four hundred three million, seven hundred nine thousand, nine hundred seventy-seven".