21435138768 has 40 divisors (see below), whose sum is σ = 55438380288. Its totient is φ = 7136753152.

The previous prime is 21435138749. The next prime is 21435138833. The reversal of 21435138768 is 86783153412.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 217305 + ... + 300152.

Almost surely, 2^21435138768 is an apocalyptic number.

It is an amenable number.

21435138768 is an abundant number, since it is smaller than the sum of its proper divisors (34003241520).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21435138768 is a wasteful number, since it uses less digits than its factorization.

21435138768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 518331 (or 518325 counting only the distinct ones).

The product of its digits is 967680, while the sum is 48.

The spelling of 21435138768 in words is "twenty-one billion, four hundred thirty-five million, one hundred thirty-eight thousand, seven hundred sixty-eight".