21901222860 has 384 divisors, whose sum is σ = 74132029440. Its totient is φ = 4771353600.

The previous prime is 21901222799. The next prime is 21901222867. The reversal of 21901222860 is 6822210912.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (21901222867) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 20602689 + ... + 20603751.

It is an arithmetic number, because the mean of its divisors is an integer number (193052160).

Almost surely, 2^21901222860 is an apocalyptic number.

21901222860 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 21901222860, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37066014720).

21901222860 is an abundant number, since it is smaller than the sum of its proper divisors (52230806580).

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

21901222860 is a wasteful number, since it uses less digits than its factorization.

21901222860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1189 (or 1187 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 33.

The spelling of 21901222860 in words is "twenty-one billion, nine hundred one million, two hundred twenty-two thousand, eight hundred sixty".