261977407 has 4 divisors (see below), whose sum is σ = 262063296. Its totient is φ = 261891520.

The previous prime is 261977393. The next prime is 261977411. The reversal of 261977407 is 704779162.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 704779162 = 2 ⋅352389581.

It is a cyclic number.

It is not a de Polignac number, because 261977407 - 2¹⁹ = 261453119 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261977207) 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, 38194 + ... + 44527.

It is an arithmetic number, because the mean of its divisors is an integer number (65515824).

Almost surely, 2^261977407 is an apocalyptic number.

261977407 is a deficient number, since it is larger than the sum of its proper divisors (85889).

261977407 is an equidigital number, since it uses as much as digits as its factorization.

261977407 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85888.

The product of its (nonzero) digits is 148176, while the sum is 43.

The square root of 261977407 is about 16185.7161410918. The cubic root of 261977407 is about 639.8643975403.

The spelling of 261977407 in words is "two hundred sixty-one million, nine hundred seventy-seven thousand, four hundred seven".