1261642536 has 96 divisors (see below), whose sum is σ = 4260110400. Its totient is φ = 327697920.

The previous prime is 1261642531. The next prime is 1261642589. The reversal of 1261642536 is 6352461621.

1261642536 is a `hidden beast` number, since 1 + 2 + 6 + 1 + 642 + 5 + 3 + 6 = 666.

It is a super-2 number, since 2×1261642536² = 3183483777289022592, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 1261642536.

It is not an unprimeable number, because it can be changed into a prime (1261642531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 108241 + ... + 119328.

It is an arithmetic number, because the mean of its divisors is an integer number (44376150).

Almost surely, 2^1261642536 is an apocalyptic number.

It is an amenable number.

1261642536 is an abundant number, since it is smaller than the sum of its proper divisors (2998467864).

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

1261642536 is a wasteful number, since it uses less digits than its factorization.

1261642536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227599 (or 227592 counting only the distinct ones).

The product of its digits is 51840, while the sum is 36.

The square root of 1261642536 is about 35519.6077681046. The cubic root of 1261642536 is about 1080.5514262239.

The spelling of 1261642536 in words is "one billion, two hundred sixty-one million, six hundred forty-two thousand, five hundred thirty-six".