21159823636 has 96 divisors (see below), whose sum is σ = 48266330112. Its totient is φ = 7900485120.

The previous prime is 21159823631. The next prime is 21159823637. The reversal of 21159823636 is 63632895112.

It is a Harshad number since it is a multiple of its sum of digits (46).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21159823631) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 308215 + ... + 370561.

It is an arithmetic number, because the mean of its divisors is an integer number (502774272).

Almost surely, 2^21159823636 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21159823636, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24133165056).

21159823636 is an abundant number, since it is smaller than the sum of its proper divisors (27106506476).

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

21159823636 is a wasteful number, since it uses less digits than its factorization.

21159823636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 62429 (or 62427 counting only the distinct ones).

The product of its digits is 466560, while the sum is 46.

The spelling of 21159823636 in words is "twenty-one billion, one hundred fifty-nine million, eight hundred twenty-three thousand, six hundred thirty-six".