1340723561 has 4 divisors (see below), whose sum is σ = 1350958224. Its totient is φ = 1330488900.

The previous prime is 1340723507. The next prime is 1340723597. The reversal of 1340723561 is 1653270431.

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 1340723561 - 2¹⁸ = 1340461417 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1340723861) 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, 5117135 + ... + 5117396.

It is an arithmetic number, because the mean of its divisors is an integer number (337739556).

Almost surely, 2^1340723561 is an apocalyptic number.

It is an amenable number.

1340723561 is a deficient number, since it is larger than the sum of its proper divisors (10234663).

1340723561 is a wasteful number, since it uses less digits than its factorization.

1340723561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10234662.

The product of its (nonzero) digits is 15120, while the sum is 32.

The square root of 1340723561 is about 36615.8921917792. The cubic root of 1340723561 is about 1102.6721703274.

Adding to 1340723561 its reverse (1653270431), we get a palindrome (2993993992).

The spelling of 1340723561 in words is "one billion, three hundred forty million, seven hundred twenty-three thousand, five hundred sixty-one".