21273878441 has 2 divisors, whose sum is σ = 21273878442. Its totient is φ = 21273878440.

The previous prime is 21273878411. The next prime is 21273878467. The reversal of 21273878441 is 14487837212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12056918416 + 9216960025 = 109804^2 + 96005^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21273878441 is a prime.

It is not a weakly prime, because it can be changed into another prime (21273878411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10636939220 + 10636939221.

It is an arithmetic number, because the mean of its divisors is an integer number (10636939221).

Almost surely, 2^21273878441 is an apocalyptic number.

It is an amenable number.

21273878441 is a deficient number, since it is larger than the sum of its proper divisors (1).

21273878441 is an equidigital number, since it uses as much as digits as its factorization.

21273878441 is an evil number, because the sum of its binary digits is even.

The product of its digits is 602112, while the sum is 47.

The spelling of 21273878441 in words is "twenty-one billion, two hundred seventy-three million, eight hundred seventy-eight thousand, four hundred forty-one".