1261643610 has 128 divisors (see below), whose sum is σ = 3404021760. Its totient is φ = 297583616.

The previous prime is 1261643599. The next prime is 1261643629. The reversal of 1261643610 is 163461621.

1261643610 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 691159 + ... + 692981.

It is an arithmetic number, because the mean of its divisors is an integer number (26593920).

Almost surely, 2^1261643610 is an apocalyptic number.

1261643610 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1261643610, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1702010880).

1261643610 is an abundant number, since it is smaller than the sum of its proper divisors (2142378150).

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

1261643610 is a wasteful number, since it uses less digits than its factorization.

1261643610 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1932.

The product of its (nonzero) digits is 5184, while the sum is 30.

The square root of 1261643610 is about 35519.6228865116. The cubic root of 1261643610 is about 1080.5517328379.

The spelling of 1261643610 in words is "one billion, two hundred sixty-one million, six hundred forty-three thousand, six hundred ten".