21435977984 has 18 divisors (see below), whose sum is σ = 42788222190. Its totient is φ = 10717988864.

The previous prime is 21435977963. The next prime is 21435978007. The reversal of 21435977984 is 48977953412.

It can be written as a sum of positive squares in only one way, i.e., 18149478400 + 3286499584 = 134720^2 + 57328^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41866889 + ... + 41867400.

It is an arithmetic number, because the mean of its divisors is an integer number (2377123455).

Almost surely, 2^21435977984 is an apocalyptic number.

It is an amenable number.

21435977984 is a deficient number, since it is larger than the sum of its proper divisors (21352244206).

21435977984 is an frugal number, since it uses more digits than its factorization.

21435977984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83734305 (or 83734291 counting only the distinct ones).

The product of its digits is 15240960, while the sum is 59.

The spelling of 21435977984 in words is "twenty-one billion, four hundred thirty-five million, nine hundred seventy-seven thousand, nine hundred eighty-four".