21127289389 has 2 divisors, whose sum is σ = 21127289390. Its totient is φ = 21127289388.

The previous prime is 21127289371. The next prime is 21127289399. The reversal of 21127289389 is 98398272112.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20929408900 + 197880489 = 144670^2 + 14067^2 .

It is a cyclic number.

It is not a de Polignac number, because 21127289389 - 2¹¹ = 21127287341 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21127289329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10563644694 + 10563644695.

It is an arithmetic number, because the mean of its divisors is an integer number (10563644695).

Almost surely, 2^21127289389 is an apocalyptic number.

It is an amenable number.

21127289389 is a deficient number, since it is larger than the sum of its proper divisors (1).

21127289389 is an equidigital number, since it uses as much as digits as its factorization.

21127289389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 870912, while the sum is 52.

The spelling of 21127289389 in words is "twenty-one billion, one hundred twenty-seven million, two hundred eighty-nine thousand, three hundred eighty-nine".