261971377 has 8 divisors (see below), whose sum is σ = 281182536. Its totient is φ = 243182592.

The previous prime is 261971371. The next prime is 261971383. The reversal of 261971377 is 773179162.

It is an interprime number because it is at equal distance from previous prime (261971371) and next prime (261971383).

It can be written as a sum of positive squares in 4 ways, for example, as 72743841 + 189227536 = 8529^2 + 13756^2 .

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 261971377 - 2⁷ = 261971249 is a prime.

It is a super-2 number, since 2×261971377² = 137258004734552258, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261971371) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 104308 + ... + 106789.

It is an arithmetic number, because the mean of its divisors is an integer number (35147817).

Almost surely, 2^261971377 is an apocalyptic number.

It is an amenable number.

261971377 is a deficient number, since it is larger than the sum of its proper divisors (19211159).

261971377 is a wasteful number, since it uses less digits than its factorization.

261971377 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211187.

The product of its digits is 111132, while the sum is 43.

The square root of 261971377 is about 16185.5298646662. The cubic root of 261971377 is about 639.8594881959.

The spelling of 261971377 in words is "two hundred sixty-one million, nine hundred seventy-one thousand, three hundred seventy-seven".