1261685145 has 32 divisors (see below), whose sum is σ = 2360742912. Its totient is φ = 563355072.

The previous prime is 1261685129. The next prime is 1261685203. The reversal of 1261685145 is 5415861621.

1261685145 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 1261685145 - 2⁴ = 1261685129 is a prime.

It is a super-2 number, since 2×1261685145² = 3183698810227342050, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 135207 + ... + 144236.

It is an arithmetic number, because the mean of its divisors is an integer number (73773216).

Almost surely, 2^1261685145 is an apocalyptic number.

1261685145 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1261685145 is a deficient number, since it is larger than the sum of its proper divisors (1099057767).

1261685145 is a wasteful number, since it uses less digits than its factorization.

1261685145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279501.

The product of its digits is 57600, while the sum is 39.

The square root of 1261685145 is about 35520.2075585152. The cubic root of 1261685145 is about 1080.5635904453.

The spelling of 1261685145 in words is "one billion, two hundred sixty-one million, six hundred eighty-five thousand, one hundred forty-five".