1365542721 has 24 divisors (see below), whose sum is σ = 2012063976. Its totient is φ = 892120320.

The previous prime is 1365542719. The next prime is 1365542771. The reversal of 1365542721 is 1272455631.

1365542721 is a `hidden beast` number, since 1 + 36 + 554 + 2 + 72 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 389667600 + 975875121 = 19740^2 + 31239^2 .

It is not a de Polignac number, because 1365542721 - 2¹ = 1365542719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1365542771) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 705471 + ... + 707403.

It is an arithmetic number, because the mean of its divisors is an integer number (83835999).

Almost surely, 2^1365542721 is an apocalyptic number.

It is an amenable number.

1365542721 is a deficient number, since it is larger than the sum of its proper divisors (646521255).

1365542721 is a wasteful number, since it uses less digits than its factorization.

1365542721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3473 (or 3470 counting only the distinct ones).

The product of its digits is 50400, while the sum is 36.

The square root of 1365542721 is about 36953.2504794910. The cubic root of 1365542721 is about 1109.4347475072.

The spelling of 1365542721 in words is "one billion, three hundred sixty-five million, five hundred forty-two thousand, seven hundred twenty-one".