1261542899 has 8 divisors (see below), whose sum is σ = 1293987408. Its totient is φ = 1229178240.

The previous prime is 1261542869. The next prime is 1261542907. The reversal of 1261542899 is 9982451621.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1261542899 - 2²⁸ = 993107443 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1261542809) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12719 + ... + 51815.

It is an arithmetic number, because the mean of its divisors is an integer number (161748426).

Almost surely, 2^1261542899 is an apocalyptic number.

1261542899 is a deficient number, since it is larger than the sum of its proper divisors (32444509).

1261542899 is an equidigital number, since it uses as much as digits as its factorization.

1261542899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39925.

The product of its digits is 311040, while the sum is 47.

The square root of 1261542899 is about 35518.2051770638. The cubic root of 1261542899 is about 1080.5229803069.

The spelling of 1261542899 in words is "one billion, two hundred sixty-one million, five hundred forty-two thousand, eight hundred ninety-nine".