21640184657340 has 24 divisors (see below), whose sum is σ = 60592517040720. Its totient is φ = 5770715908608.

The previous prime is 21640184657321. The next prime is 21640184657381. The reversal of 21640184657340 is 4375648104612.

It is a congruent number.

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, 180334872085 + ... + 180334872204.

It is an arithmetic number, because the mean of its divisors is an integer number (2524688210030).

Almost surely, 2^{21640184657340} is an apocalyptic number.

21640184657340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21640184657340 is an abundant number, since it is smaller than the sum of its proper divisors (38952332383380).

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

21640184657340 is a wasteful number, since it uses less digits than its factorization.

21640184657340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360669744301 (or 360669744299 counting only the distinct ones).

The product of its (nonzero) digits is 3870720, while the sum is 51.

The spelling of 21640184657340 in words is "twenty-one trillion, six hundred forty billion, one hundred eighty-four million, six hundred fifty-seven thousand, three hundred forty".