21000403244 has 24 divisors (see below), whose sum is σ = 38177092800. Its totient is φ = 10095693440.

The previous prime is 21000403241. The next prime is 21000403247. The reversal of 21000403244 is 44230400012.

It is an interprime number because it is at equal distance from previous prime (21000403241) and next prime (21000403247).

It is not an unprimeable number, because it can be changed into a prime (21000403241) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 351017 + ... + 406464.

It is an arithmetic number, because the mean of its divisors is an integer number (1590712200).

Almost surely, 2^21000403244 is an apocalyptic number.

It is an amenable number.

21000403244 is a deficient number, since it is larger than the sum of its proper divisors (17176689556).

21000403244 is a wasteful number, since it uses less digits than its factorization.

21000403244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 757753 (or 757751 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 20.

Adding to 21000403244 its reverse (44230400012), we get a palindrome (65230803256).

The spelling of 21000403244 in words is "twenty-one billion, four hundred three thousand, two hundred forty-four".