21649307778223 has 8 divisors (see below), whose sum is σ = 21710866297536. Its totient is φ = 21587750553600.

The previous prime is 21649307778181. The next prime is 21649307778233. The reversal of 21649307778223 is 32287770394612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21649307778223 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21649307778233) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 40456618 + ... + 40988248.

It is an arithmetic number, because the mean of its divisors is an integer number (2713858287192).

Almost surely, 2^{21649307778223} is an apocalyptic number.

21649307778223 is a deficient number, since it is larger than the sum of its proper divisors (61558519313).

21649307778223 is a wasteful number, since it uses less digits than its factorization.

21649307778223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 647345.

The product of its (nonzero) digits is 42674688, while the sum is 61.

The spelling of 21649307778223 in words is "twenty-one trillion, six hundred forty-nine billion, three hundred seven million, seven hundred seventy-eight thousand, two hundred twenty-three".