21002201178 has 64 divisors (see below), whose sum is σ = 49118192640. Its totient is φ = 5863024512.

The previous prime is 21002201177. The next prime is 21002201179. The reversal of 21002201178 is 87110220012.

It is an interprime number because it is at equal distance from previous prime (21002201177) and next prime (21002201179).

It is not an unprimeable number, because it can be changed into a prime (21002201177) 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, 296053 + ... + 360071.

It is an arithmetic number, because the mean of its divisors is an integer number (767471760).

Almost surely, 2^21002201178 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21002201178, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24559096320).

21002201178 is an abundant number, since it is smaller than the sum of its proper divisors (28115991462).

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

21002201178 is a wasteful number, since it uses less digits than its factorization.

21002201178 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64211.

The product of its (nonzero) digits is 448, while the sum is 24.

The spelling of 21002201178 in words is "twenty-one billion, two million, two hundred one thousand, one hundred seventy-eight".