261143857 has 4 divisors (see below), whose sum is σ = 281231860. Its totient is φ = 241055856.

The previous prime is 261143833. The next prime is 261143873. The reversal of 261143857 is 758341162.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 74028816 + 187115041 = 8604^2 + 13679^2 .

It is a cyclic number.

It is not a de Polignac number, because 261143857 - 2¹¹ = 261141809 is a prime.

It is a super-2 number, since 2×261143857² = 136392228097672898, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (261141857) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10043982 + ... + 10044007.

It is an arithmetic number, because the mean of its divisors is an integer number (70307965).

Almost surely, 2^261143857 is an apocalyptic number.

It is an amenable number.

261143857 is a deficient number, since it is larger than the sum of its proper divisors (20088003).

261143857 is a wasteful number, since it uses less digits than its factorization.

261143857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20088002.

The product of its digits is 40320, while the sum is 37.

The square root of 261143857 is about 16159.9460704546. The cubic root of 261143857 is about 639.1850442446.

The spelling of 261143857 in words is "two hundred sixty-one million, one hundred forty-three thousand, eight hundred fifty-seven".