21938587673 has 2 divisors, whose sum is σ = 21938587674. Its totient is φ = 21938587672.

The previous prime is 21938587661. The next prime is 21938587721. The reversal of 21938587673 is 37678583912.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19843511689 + 2095075984 = 140867^2 + 45772^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21938587673 is a prime.

It is not a weakly prime, because it can be changed into another prime (21938580673) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10969293836 + 10969293837.

It is an arithmetic number, because the mean of its divisors is an integer number (10969293837).

Almost surely, 2^21938587673 is an apocalyptic number.

It is an amenable number.

21938587673 is a deficient number, since it is larger than the sum of its proper divisors (1).

21938587673 is an equidigital number, since it uses as much as digits as its factorization.

21938587673 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15240960, while the sum is 59.

The spelling of 21938587673 in words is "twenty-one billion, nine hundred thirty-eight million, five hundred eighty-seven thousand, six hundred seventy-three".