261907164 has 144 divisors (see below), whose sum is σ = 725018112. Its totient is φ = 79491456.

The previous prime is 261907123. The next prime is 261907169. The reversal of 261907164 is 461709162.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261907169) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2542737 + ... + 2542839.

It is an arithmetic number, because the mean of its divisors is an integer number (5034848).

Almost surely, 2^261907164 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261907164, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (362509056).

261907164 is an abundant number, since it is smaller than the sum of its proper divisors (463110948).

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

261907164 is a wasteful number, since it uses less digits than its factorization.

261907164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256 (or 251 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 261907164 is about 16183.5460885431. The cubic root of 261907164 is about 639.8072042972.

The spelling of 261907164 in words is "two hundred sixty-one million, nine hundred seven thousand, one hundred sixty-four".