261749070 has 160 divisors (see below), whose sum is σ = 795057120. Its totient is φ = 61205760.

The previous prime is 261749011. The next prime is 261749077. The reversal of 261749070 is 70947162.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261749077) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 257884 + ... + 258896.

It is an arithmetic number, because the mean of its divisors is an integer number (4969107).

Almost surely, 2^261749070 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261749070, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (397528560).

261749070 is an abundant number, since it is smaller than the sum of its proper divisors (533308050).

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

261749070 is a wasteful number, since it uses less digits than its factorization.

261749070 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1072 (or 1063 counting only the distinct ones).

The product of its (nonzero) digits is 21168, while the sum is 36.

The square root of 261749070 is about 16178.6609458261. The cubic root of 261749070 is about 639.6784436101.

The spelling of 261749070 in words is "two hundred sixty-one million, seven hundred forty-nine thousand, seventy".