1373821261 has 2 divisors, whose sum is σ = 1373821262. Its totient is φ = 1373821260.

The previous prime is 1373821259. The next prime is 1373821271. The reversal of 1373821261 is 1621283731.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1363898761 + 9922500 = 36931^2 + 3150^2 .

It is a cyclic number.

It is not a de Polignac number, because 1373821261 - 2¹ = 1373821259 is a prime.

It is a super-3 number, since 3×1373821261³ (a number of 28 digits) contains 333 as substring.

Together with 1373821259, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1373821231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 686910630 + 686910631.

It is an arithmetic number, because the mean of its divisors is an integer number (686910631).

Almost surely, 2^1373821261 is an apocalyptic number.

It is an amenable number.

1373821261 is a deficient number, since it is larger than the sum of its proper divisors (1).

1373821261 is an equidigital number, since it uses as much as digits as its factorization.

1373821261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12096, while the sum is 34.

The square root of 1373821261 is about 37065.0949142181. The cubic root of 1373821261 is about 1111.6721978266.

The spelling of 1373821261 in words is "one billion, three hundred seventy-three million, eight hundred twenty-one thousand, two hundred sixty-one".