21357274789 has 2 divisors, whose sum is σ = 21357274790. Its totient is φ = 21357274788.

The previous prime is 21357274769. The next prime is 21357274817. The reversal of 21357274789 is 98747275312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19833933889 + 1523340900 = 140833^2 + 39030^2 .

It is a cyclic number.

It is not a de Polignac number, because 21357274789 - 2²¹ = 21355177637 is a prime.

It is a super-2 number, since 2×21357274789² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21357274769) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10678637394 + 10678637395.

It is an arithmetic number, because the mean of its divisors is an integer number (10678637395).

Almost surely, 2^21357274789 is an apocalyptic number.

It is an amenable number.

21357274789 is a deficient number, since it is larger than the sum of its proper divisors (1).

21357274789 is an equidigital number, since it uses as much as digits as its factorization.

21357274789 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5927040, while the sum is 55.

The spelling of 21357274789 in words is "twenty-one billion, three hundred fifty-seven million, two hundred seventy-four thousand, seven hundred eighty-nine".