21272773397 has 2 divisors, whose sum is σ = 21272773398. Its totient is φ = 21272773396.

The previous prime is 21272773381. The next prime is 21272773411. The reversal of 21272773397 is 79337727212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14046753361 + 7226020036 = 118519^2 + 85006^2 .

It is a cyclic number.

It is not a de Polignac number, because 21272773397 - 2⁴ = 21272773381 is a prime.

It is a super-2 number, since 2×21272773397² (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 (21272773307) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10636386698 + 10636386699.

It is an arithmetic number, because the mean of its divisors is an integer number (10636386699).

Almost surely, 2^21272773397 is an apocalyptic number.

It is an amenable number.

21272773397 is a deficient number, since it is larger than the sum of its proper divisors (1).

21272773397 is an equidigital number, since it uses as much as digits as its factorization.

21272773397 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1555848, while the sum is 50.

The spelling of 21272773397 in words is "twenty-one billion, two hundred seventy-two million, seven hundred seventy-three thousand, three hundred ninety-seven".