21054174389 has 2 divisors, whose sum is σ = 21054174390. Its totient is φ = 21054174388.

The previous prime is 21054174371. The next prime is 21054174413. The reversal of 21054174389 is 98347145012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11617606225 + 9436568164 = 107785^2 + 97142^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21054174389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21054174359) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10527087194 + 10527087195.

It is an arithmetic number, because the mean of its divisors is an integer number (10527087195).

Almost surely, 2^21054174389 is an apocalyptic number.

It is an amenable number.

21054174389 is a deficient number, since it is larger than the sum of its proper divisors (1).

21054174389 is an equidigital number, since it uses as much as digits as its factorization.

21054174389 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 241920, while the sum is 44.

The spelling of 21054174389 in words is "twenty-one billion, fifty-four million, one hundred seventy-four thousand, three hundred eighty-nine".