261918426 has 48 divisors (see below), whose sum is σ = 664765920. Its totient is φ = 68029920.

The previous prime is 261918383. The next prime is 261918443. The reversal of 261918426 is 624819162.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 37261 + ... + 43728.

It is an arithmetic number, because the mean of its divisors is an integer number (13849290).

Almost surely, 2^261918426 is an apocalyptic number.

261918426 is an abundant number, since it is smaller than the sum of its proper divisors (402847494).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261918426 is a wasteful number, since it uses less digits than its factorization.

261918426 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81019 (or 81012 counting only the distinct ones).

The product of its digits is 41472, while the sum is 39.

The square root of 261918426 is about 16183.8940307949. The cubic root of 261918426 is about 639.8163747291.

The spelling of 261918426 in words is "two hundred sixty-one million, nine hundred eighteen thousand, four hundred twenty-six".