261720153 has 10 divisors (see below), whose sum is σ = 390964794. Its totient is φ = 174480048.

The previous prime is 261720149. The next prime is 261720161. The reversal of 261720153 is 351027162.

It is a happy number.

261720153 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 238795209 + 22924944 = 15453^2 + 4788^2 .

It is not a de Polignac number, because 261720153 - 2² = 261720149 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (261720103) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 1615476 + ... + 1615637.

Almost surely, 2^261720153 is an apocalyptic number.

It is an amenable number.

261720153 is a deficient number, since it is larger than the sum of its proper divisors (129244641).

261720153 is an equidigital number, since it uses as much as digits as its factorization.

261720153 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3231125 (or 3231116 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 261720153 is about 16177.7672439679. The cubic root of 261720153 is about 639.6548863627.

The spelling of 261720153 in words is "two hundred sixty-one million, seven hundred twenty thousand, one hundred fifty-three".