261513501 has 16 divisors (see below), whose sum is σ = 356408640. Its totient is φ = 170501760.

The previous prime is 261513491. The next prime is 261513509. The reversal of 261513501 is 105315162.

It is not a de Polignac number, because 261513501 - 2⁶ = 261513437 is a prime.

It is a super-2 number, since 2×261513501² = 136778622410554002, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261513509) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50145 + ... + 55113.

It is an arithmetic number, because the mean of its divisors is an integer number (22275540).

Almost surely, 2^261513501 is an apocalyptic number.

It is an amenable number.

261513501 is a deficient number, since it is larger than the sum of its proper divisors (94895139).

261513501 is a wasteful number, since it uses less digits than its factorization.

261513501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5356.

The product of its (nonzero) digits is 900, while the sum is 24.

The square root of 261513501 is about 16171.3790692074. The cubic root of 261513501 is about 639.4864866856.

Adding to 261513501 its reverse (105315162), we get a palindrome (366828663).

The spelling of 261513501 in words is "two hundred sixty-one million, five hundred thirteen thousand, five hundred one".