1553661265 has 16 divisors (see below), whose sum is σ = 2062076688. Its totient is φ = 1116308736.

The previous prime is 1553661259. The next prime is 1553661269. The reversal of 1553661265 is 5621663551.

It can be written as a sum of positive squares in 8 ways, for example, as 125350416 + 1428310849 = 11196^2 + 37793^2 .

It is a cyclic number.

It is not a de Polignac number, because 1553661265 - 2⁵ = 1553661233 is a prime.

It is a super-2 number, since 2×1553661265² = 4827726652722800450, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1553661269) 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, 320602 + ... + 325411.

It is an arithmetic number, because the mean of its divisors is an integer number (128879793).

Almost surely, 2^1553661265 is an apocalyptic number.

It is an amenable number.

1553661265 is a deficient number, since it is larger than the sum of its proper divisors (508415423).

1553661265 is a wasteful number, since it uses less digits than its factorization.

1553661265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 646068.

The product of its digits is 162000, while the sum is 40.

The square root of 1553661265 is about 39416.5100560666. The cubic root of 1553661265 is about 1158.2050283617.

The spelling of 1553661265 in words is "one billion, five hundred fifty-three million, six hundred sixty-one thousand, two hundred sixty-five".