21464085778 has 4 divisors (see below), whose sum is σ = 32196128670. Its totient is φ = 10732042888.

The previous prime is 21464085749. The next prime is 21464085787. The reversal of 21464085778 is 87758046412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 12369221089 + 9094864689 = 111217^2 + 95367^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5366021443 + ... + 5366021446.

Almost surely, 2^21464085778 is an apocalyptic number.

21464085778 is a deficient number, since it is larger than the sum of its proper divisors (10732042892).

21464085778 is a wasteful number, since it uses less digits than its factorization.

21464085778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10732042891.

The product of its (nonzero) digits is 3010560, while the sum is 52.

The spelling of 21464085778 in words is "twenty-one billion, four hundred sixty-four million, eighty-five thousand, seven hundred seventy-eight".