21365971860 has 192 divisors, whose sum is σ = 61892812800. Its totient is φ = 5505297408.

The previous prime is 21365971853. The next prime is 21365971871. The reversal of 21365971860 is 6817956312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 52239336 + ... + 52239744.

It is an arithmetic number, because the mean of its divisors is an integer number (322358400).

Almost surely, 2^21365971860 is an apocalyptic number.

21365971860 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 21365971860, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30946406400).

21365971860 is an abundant number, since it is smaller than the sum of its proper divisors (40526840940).

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

21365971860 is a wasteful number, since it uses less digits than its factorization.

21365971860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 710 (or 708 counting only the distinct ones).

The product of its (nonzero) digits is 544320, while the sum is 48.

The spelling of 21365971860 in words is "twenty-one billion, three hundred sixty-five million, nine hundred seventy-one thousand, eight hundred sixty".