21649797040 has 40 divisors (see below), whose sum is σ = 50455989360. Its totient is φ = 8639237376.

The previous prime is 21649797031. The next prime is 21649797053. The reversal of 21649797040 is 4079794612.

It is a tau number, because it is divible by the number of its divisors (40).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 289419 + ... + 356458.

It is an arithmetic number, because the mean of its divisors is an integer number (1261399734).

Almost surely, 2^21649797040 is an apocalyptic number.

21649797040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21649797040 is an abundant number, since it is smaller than the sum of its proper divisors (28806192320).

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

21649797040 is a wasteful number, since it uses less digits than its factorization.

21649797040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 646309 (or 646303 counting only the distinct ones).

The product of its (nonzero) digits is 762048, while the sum is 49.

The spelling of 21649797040 in words is "twenty-one billion, six hundred forty-nine million, seven hundred ninety-seven thousand, forty".