21500167416421 has 24 divisors (see below), whose sum is σ = 22817726702784. Its totient is φ = 20255328279360.

The previous prime is 21500167416323. The next prime is 21500167416473. The reversal of 21500167416421 is 12461476100512.

It is a happy number.

It is not a de Polignac number, because 21500167416421 - 2⁷ = 21500167416293 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 (21500167419421) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 66034536 + ... + 66359326.

It is an arithmetic number, because the mean of its divisors is an integer number (950738612616).

Almost surely, 2^{21500167416421} is an apocalyptic number.

It is an amenable number.

21500167416421 is a deficient number, since it is larger than the sum of its proper divisors (1317559286363).

21500167416421 is a wasteful number, since it uses less digits than its factorization.

21500167416421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 325849 (or 325830 counting only the distinct ones).

The product of its (nonzero) digits is 80640, while the sum is 40.

The spelling of 21500167416421 in words is "twenty-one trillion, five hundred billion, one hundred sixty-seven million, four hundred sixteen thousand, four hundred twenty-one".