1253165661 has 60 divisors (see below), whose sum is σ = 2129103900. Its totient is φ = 733138560.

The previous prime is 1253165611. The next prime is 1253165689. The reversal of 1253165661 is 1665613521.

1253165661 is a `hidden beast` number, since 1 + 2 + 531 + 65 + 6 + 61 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 335439225 + 917726436 = 18315^2 + 30294^2 .

It is not a de Polignac number, because 1253165661 - 2⁶ = 1253165597 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1253165611) by changing a digit.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 282025 + ... + 286433.

It is an arithmetic number, because the mean of its divisors is an integer number (35485065).

Almost surely, 2^1253165661 is an apocalyptic number.

1253165661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1253165661 is a deficient number, since it is larger than the sum of its proper divisors (875938239).

1253165661 is a wasteful number, since it uses less digits than its factorization.

1253165661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4472 (or 4452 counting only the distinct ones).

The product of its digits is 32400, while the sum is 36.

The square root of 1253165661 is about 35400.0799575368. The cubic root of 1253165661 is about 1078.1259397497.

The spelling of 1253165661 in words is "one billion, two hundred fifty-three million, one hundred sixty-five thousand, six hundred sixty-one".