261907949 has 4 divisors (see below), whose sum is σ = 261960864. Its totient is φ = 261855036.

The previous prime is 261907901. The next prime is 261907957. The reversal of 261907949 is 949709162.

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, and also an emirpimes, since its reverse is a distinct semiprime: 949709162 = 2 ⋅474854581.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261907949 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 (261907979) 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, 18167 + ... + 29220.

It is an arithmetic number, because the mean of its divisors is an integer number (65490216).

Almost surely, 2^261907949 is an apocalyptic number.

It is an amenable number.

261907949 is a deficient number, since it is larger than the sum of its proper divisors (52915).

261907949 is an equidigital number, since it uses as much as digits as its factorization.

261907949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52914.

The product of its (nonzero) digits is 244944, while the sum is 47.

The square root of 261907949 is about 16183.5703415532. The cubic root of 261907949 is about 639.8078435163.

The spelling of 261907949 in words is "two hundred sixty-one million, nine hundred seven thousand, nine hundred forty-nine".