21208023396 has 360 divisors, whose sum is σ = 68379804640. Its totient is φ = 5682845952.

The previous prime is 21208023391. The next prime is 21208023401. The reversal of 21208023396 is 69332080212.

It is an interprime number because it is at equal distance from previous prime (21208023391) and next prime (21208023401).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21208023396.

It is not an unprimeable number, because it can be changed into a prime (21208023391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 74939871 + ... + 74940153.

Almost surely, 2^21208023396 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 21208023396, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34189902320).

21208023396 is an abundant number, since it is smaller than the sum of its proper divisors (47171781244).

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

21208023396 is a wasteful number, since it uses less digits than its factorization.

21208023396 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 358 (or 312 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 36.

The spelling of 21208023396 in words is "twenty-one billion, two hundred eight million, twenty-three thousand, three hundred ninety-six".