21020961600 has 252 divisors, whose sum is σ = 78646771840. Its totient is φ = 5310489600.

The previous prime is 21020961593. The next prime is 21020961607. The reversal of 21020961600 is 616902012.

21020961600 is a `hidden beast` number, since 21 + 0 + 20 + 9 + 616 + 0 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (21020961593) and next prime (21020961607).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020961607) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 235185 + ... + 312015.

Almost surely, 2^21020961600 is an apocalyptic number.

21020961600 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21020961600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39323385920).

21020961600 is an abundant number, since it is smaller than the sum of its proper divisors (57625810240).

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

21020961600 is a wasteful number, since it uses less digits than its factorization.

21020961600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76878 (or 76860 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The spelling of 21020961600 in words is "twenty-one billion, twenty million, nine hundred sixty-one thousand, six hundred".