21649947000 has 256 divisors, whose sum is σ = 73963169280. Its totient is φ = 5228928000.

The previous prime is 21649946951. The next prime is 21649947017. The reversal of 21649947000 is 74994612.

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, 10129932 + ... + 10132068.

It is an arithmetic number, because the mean of its divisors is an integer number (288918630).

Almost surely, 2^21649947000 is an apocalyptic number.

21649947000 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 21649947000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36981584640).

21649947000 is an abundant number, since it is smaller than the sum of its proper divisors (52313222280).

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

21649947000 is a wasteful number, since it uses less digits than its factorization.

21649947000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2479 (or 2465 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 42.

The spelling of 21649947000 in words is "twenty-one billion, six hundred forty-nine million, nine hundred forty-seven thousand".