1361275721 has 16 divisors (see below), whose sum is σ = 1489719168. Its totient is φ = 1236384000.

The previous prime is 1361275681. The next prime is 1361275739. The reversal of 1361275721 is 1275721631.

It is a cyclic number.

It is not a de Polignac number, because 1361275721 - 2¹⁴ = 1361259337 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1361275021) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 206801 + ... + 213281.

It is an arithmetic number, because the mean of its divisors is an integer number (93107448).

Almost surely, 2^1361275721 is an apocalyptic number.

It is an amenable number.

1361275721 is a deficient number, since it is larger than the sum of its proper divisors (128443447).

1361275721 is a wasteful number, since it uses less digits than its factorization.

1361275721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6752.

The product of its digits is 17640, while the sum is 35.

The square root of 1361275721 is about 36895.4701962179. The cubic root of 1361275721 is about 1108.2779675184.

The spelling of 1361275721 in words is "one billion, three hundred sixty-one million, two hundred seventy-five thousand, seven hundred twenty-one".