1261001016 has 144 divisors (see below), whose sum is σ = 3826138680. Its totient is φ = 374774400.

The previous prime is 1261001009. The next prime is 1261001029. The reversal of 1261001016 is 6101001621.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a self number, because there is not a number n which added to its sum of digits gives 1261001016.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 460371 + ... + 463101.

Almost surely, 2^1261001016 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1261001016, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1913069340).

1261001016 is an abundant number, since it is smaller than the sum of its proper divisors (2565137664).

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

1261001016 is a wasteful number, since it uses less digits than its factorization.

1261001016 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2818 (or 2800 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 1261001016 is about 35510.5761147295. The cubic root of 1261001016 is about 1080.3682489090.

Adding to 1261001016 its reverse (6101001621), we get a palindrome (7362002637).

The spelling of 1261001016 in words is "one billion, two hundred sixty-one million, one thousand, sixteen".