21815917630 has 48 divisors (see below), whose sum is σ = 42999744240. Its totient is φ = 7964546304.

The previous prime is 21815917619. The next prime is 21815917639. The reversal of 21815917630 is 3671951812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21815917639) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 77889 + ... + 222931.

It is an arithmetic number, because the mean of its divisors is an integer number (895828005).

Almost surely, 2^21815917630 is an apocalyptic number.

21815917630 is a deficient number, since it is larger than the sum of its proper divisors (21183826610).

21815917630 is a wasteful number, since it uses less digits than its factorization.

21815917630 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145165 (or 145152 counting only the distinct ones).

The product of its (nonzero) digits is 90720, while the sum is 43.

The spelling of 21815917630 in words is "twenty-one billion, eight hundred fifteen million, nine hundred seventeen thousand, six hundred thirty".