261396720 has 400 divisors, whose sum is σ = 1020872160. Its totient is φ = 61544448.

The previous prime is 261396703. The next prime is 261396767. The reversal of 261396720 is 27693162.

261396720 is a `hidden beast` number, since 261 + 396 + 7 + 2 + 0 = 666.

261396720 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 2442907 + ... + 2443013.

Almost surely, 2^261396720 is an apocalyptic number.

261396720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261396720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (510436080).

261396720 is an abundant number, since it is smaller than the sum of its proper divisors (759475440).

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

261396720 is a wasteful number, since it uses less digits than its factorization.

261396720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174 (or 159 counting only the distinct ones).

The product of its (nonzero) digits is 27216, while the sum is 36.

The square root of 261396720 is about 16167.7679349996. The cubic root of 261396720 is about 639.3912832000.

The spelling of 261396720 in words is "two hundred sixty-one million, three hundred ninety-six thousand, seven hundred twenty".