1315023781 has 4 divisors (see below), whose sum is σ = 1372198752. Its totient is φ = 1257848812.

The previous prime is 1315023767. The next prime is 1315023799. The reversal of 1315023781 is 1873205131.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1315023781 - 2¹³ = 1315015589 is a prime.

It is a super-2 number, since 2×1315023781² = 3458575089191071922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1315023701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28587451 + ... + 28587496.

It is an arithmetic number, because the mean of its divisors is an integer number (343049688).

Almost surely, 2^1315023781 is an apocalyptic number.

It is an amenable number.

1315023781 is a deficient number, since it is larger than the sum of its proper divisors (57174971).

1315023781 is an equidigital number, since it uses as much as digits as its factorization.

1315023781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57174970.

The product of its (nonzero) digits is 5040, while the sum is 31.

The square root of 1315023781 is about 36263.2566243022. The cubic root of 1315023781 is about 1095.5811100674.

The spelling of 1315023781 in words is "one billion, three hundred fifteen million, twenty-three thousand, seven hundred eighty-one".