1261651540545 has 160 divisors (see below), whose sum is σ = 2537509810176. Its totient is φ = 594332121600.

The previous prime is 1261651540531. The next prime is 1261651540547. The reversal of 1261651540545 is 5450451561621.

1261651540545 is a `hidden beast` number, since 1 + 2 + 6 + 1 + 6 + 51 + 54 + 0 + 545 = 666.

It is not a de Polignac number, because 1261651540545 - 2⁴ = 1261651540529 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 1261651540545.

It is not an unprimeable number, because it can be changed into a prime (1261651540547) by changing a digit.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 124775040 + ... + 124785150.

Almost surely, 2^{1261651540545} is an apocalyptic number.

1261651540545 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1261651540545 is an abundant number, since it is smaller than the sum of its proper divisors (1275858269631).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1261651540545 is a wasteful number, since it uses less digits than its factorization.

1261651540545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10933 (or 10924 counting only the distinct ones).

The product of its (nonzero) digits is 720000, while the sum is 45.

The spelling of 1261651540545 in words is "one trillion, two hundred sixty-one billion, six hundred fifty-one million, five hundred forty thousand, five hundred forty-five".