261666051 has 16 divisors (see below), whose sum is σ = 357540480. Its totient is φ = 170130240.

The previous prime is 261666047. The next prime is 261666103. The reversal of 261666051 is 150666162.

261666051 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 261666051 - 2² = 261666047 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261666151) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 124215 + ... + 126303.

It is an arithmetic number, because the mean of its divisors is an integer number (22346280).

Almost surely, 2^261666051 is an apocalyptic number.

261666051 is a deficient number, since it is larger than the sum of its proper divisors (95874429).

261666051 is a wasteful number, since it uses less digits than its factorization.

261666051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3106.

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 261666051 is about 16176.0950479403. The cubic root of 261666051 is about 639.6108074829.

The spelling of 261666051 in words is "two hundred sixty-one million, six hundred sixty-six thousand, fifty-one".