261547381 has 4 divisors (see below), whose sum is σ = 261660064. Its totient is φ = 261434700.

The previous prime is 261547379. The next prime is 261547411. The reversal of 261547381 is 183745162.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 261547381 - 2¹ = 261547379 is a prime.

It is a super-2 number, since 2×261547381² = 136814065015918322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261547381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261547081) 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, 52785 + ... + 57526.

It is an arithmetic number, because the mean of its divisors is an integer number (65415016).

Almost surely, 2^261547381 is an apocalyptic number.

It is an amenable number.

261547381 is a deficient number, since it is larger than the sum of its proper divisors (112683).

261547381 is a wasteful number, since it uses less digits than its factorization.

261547381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112682.

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

The square root of 261547381 is about 16172.4265649902. The cubic root of 261547381 is about 639.5141014059.

The spelling of 261547381 in words is "two hundred sixty-one million, five hundred forty-seven thousand, three hundred eighty-one".