21408456771 has 18 divisors (see below), whose sum is σ = 33485024508. Its totient is φ = 13174434000.

The previous prime is 21408456761. The next prime is 21408456793. The reversal of 21408456771 is 17765480412.

21408456771 is a `hidden beast` number, since 2 + 1 + 4 + 0 + 84 + 567 + 7 + 1 = 666.

It is not a de Polignac number, because 21408456771 - 2¹⁸ = 21408194627 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21408456761) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 7036105 + ... + 7039146.

Almost surely, 2^21408456771 is an apocalyptic number.

21408456771 is a deficient number, since it is larger than the sum of its proper divisors (12076567737).

21408456771 is a wasteful number, since it uses less digits than its factorization.

21408456771 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14075283 (or 14075267 counting only the distinct ones).

The product of its (nonzero) digits is 376320, while the sum is 45.

The spelling of 21408456771 in words is "twenty-one billion, four hundred eight million, four hundred fifty-six thousand, seven hundred seventy-one".