21870894672 has 640 divisors, whose sum is σ = 77137920000. Its totient is φ = 5851422720.

The previous prime is 21870894667. The next prime is 21870894673. The reversal of 21870894672 is 27649807812.

It is a happy number.

21870894672 is a `hidden beast` number, since 21 + 87 + 0 + 89 + 467 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21870894673) 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, 146784454 + ... + 146784602.

It is an arithmetic number, because the mean of its divisors is an integer number (120528000).

Almost surely, 2^21870894672 is an apocalyptic number.

21870894672 is a gapful number since it is divisible by the number (22) 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 21870894672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38568960000).

21870894672 is an abundant number, since it is smaller than the sum of its proper divisors (55267025328).

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

21870894672 is a wasteful number, since it uses less digits than its factorization.

21870894672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 296 (or 284 counting only the distinct ones).

The product of its (nonzero) digits is 2709504, while the sum is 54.

The spelling of 21870894672 in words is "twenty-one billion, eight hundred seventy million, eight hundred ninety-four thousand, six hundred seventy-two".