21894813340644 has 96 divisors (see below), whose sum is σ = 54089182586880. Its totient is φ = 6874024531968.

The previous prime is 21894813340639. The next prime is 21894813340661. The reversal of 21894813340644 is 44604331849812.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 70559617 + ... + 70869239.

It is an arithmetic number, because the mean of its divisors is an integer number (563428985280).

Almost surely, 2^{21894813340644} 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 21894813340644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27044591293440).

21894813340644 is an abundant number, since it is smaller than the sum of its proper divisors (32194369246236).

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

21894813340644 is a wasteful number, since it uses less digits than its factorization.

21894813340644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311449 (or 311447 counting only the distinct ones).

The product of its (nonzero) digits is 15925248, while the sum is 57.

The spelling of 21894813340644 in words is "twenty-one trillion, eight hundred ninety-four billion, eight hundred thirteen million, three hundred forty thousand, six hundred forty-four".