1281172421 has 2 divisors, whose sum is σ = 1281172422. Its totient is φ = 1281172420.

The previous prime is 1281172307. The next prime is 1281172457. The reversal of 1281172421 is 1242711821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 843902500 + 437269921 = 29050^2 + 20911^2 .

It is a cyclic number.

It is not a de Polignac number, because 1281172421 - 2²² = 1276978117 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1281172721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 640586210 + 640586211.

It is an arithmetic number, because the mean of its divisors is an integer number (640586211).

Almost surely, 2^1281172421 is an apocalyptic number.

It is an amenable number.

1281172421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1281172421 is an equidigital number, since it uses as much as digits as its factorization.

1281172421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1792, while the sum is 29.

The square root of 1281172421 is about 35793.4689713082. The cubic root of 1281172421 is about 1086.0984496645.

The spelling of 1281172421 in words is "one billion, two hundred eighty-one million, one hundred seventy-two thousand, four hundred twenty-one".