1251205705 has 8 divisors (see below), whose sum is σ = 1502857800. Its totient is φ = 1000023936.

The previous prime is 1251205693. The next prime is 1251205717. The reversal of 1251205705 is 5075021521.

It is an interprime number because it is at equal distance from previous prime (1251205693) and next prime (1251205717).

It can be written as a sum of positive squares in 4 ways, for example, as 294911929 + 956293776 = 17173^2 + 30924^2 .

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 1251205705 - 2²⁵ = 1217651273 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 111700 + ... + 122389.

It is an arithmetic number, because the mean of its divisors is an integer number (187857225).

Almost surely, 2^1251205705 is an apocalyptic number.

It is an amenable number.

1251205705 is a deficient number, since it is larger than the sum of its proper divisors (251652095).

1251205705 is a wasteful number, since it uses less digits than its factorization.

1251205705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 235163.

The product of its (nonzero) digits is 3500, while the sum is 28.

The square root of 1251205705 is about 35372.3861931875. The cubic root of 1251205705 is about 1077.5635820743.

The spelling of 1251205705 in words is "one billion, two hundred fifty-one million, two hundred five thousand, seven hundred five".