261551213 has 16 divisors (see below), whose sum is σ = 327383424. Its totient is φ = 202997760.

The previous prime is 261551197. The next prime is 261551219. The reversal of 261551213 is 312155162.

It is not a de Polignac number, because 261551213 - 2⁴ = 261551197 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 (261551219) 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, 13181 + ... + 26397.

It is an arithmetic number, because the mean of its divisors is an integer number (20461464).

Almost surely, 2^261551213 is an apocalyptic number.

It is an amenable number.

261551213 is a deficient number, since it is larger than the sum of its proper divisors (65832211).

261551213 is a wasteful number, since it uses less digits than its factorization.

261551213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13492.

The product of its digits is 1800, while the sum is 26.

The square root of 261551213 is about 16172.5450378102. The cubic root of 261551213 is about 639.5172246209.

The spelling of 261551213 in words is "two hundred sixty-one million, five hundred fifty-one thousand, two hundred thirteen".