21649806140 has 12 divisors (see below), whose sum is σ = 45464592936. Its totient is φ = 8659922448.

The previous prime is 21649806053. The next prime is 21649806149. The reversal of 21649806140 is 4160894612.

It is a hoax number, since the sum of its digits (41) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21649806149) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 541245134 + ... + 541245173.

It is an arithmetic number, because the mean of its divisors is an integer number (3788716078).

Almost surely, 2^21649806140 is an apocalyptic number.

21649806140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21649806140 is an abundant number, since it is smaller than the sum of its proper divisors (23814786796).

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

21649806140 is a wasteful number, since it uses less digits than its factorization.

21649806140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1082490316 (or 1082490314 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 41.

The spelling of 21649806140 in words is "twenty-one billion, six hundred forty-nine million, eight hundred six thousand, one hundred forty".