1373601781 has 2 divisors, whose sum is σ = 1373601782. Its totient is φ = 1373601780.

The previous prime is 1373601731. The next prime is 1373601829. The reversal of 1373601781 is 1871063731.

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., 974001681 + 399600100 = 31209^2 + 19990^2 .

It is a cyclic number.

It is not a de Polignac number, because 1373601781 - 2¹⁵ = 1373569013 is a prime.

It is a super-2 number, since 2×1373601781² = 3773563705532743922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1373601781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1373601731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 686800890 + 686800891.

It is an arithmetic number, because the mean of its divisors is an integer number (686800891).

Almost surely, 2^1373601781 is an apocalyptic number.

It is an amenable number.

1373601781 is a deficient number, since it is larger than the sum of its proper divisors (1).

1373601781 is an equidigital number, since it uses as much as digits as its factorization.

1373601781 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21168, while the sum is 37.

The square root of 1373601781 is about 37062.1340589017. The cubic root of 1373601781 is about 1111.6129948780.

The spelling of 1373601781 in words is "one billion, three hundred seventy-three million, six hundred one thousand, seven hundred eighty-one".