261123507 has 20 divisors (see below), whose sum is σ = 392937336. Its totient is φ = 172804320.

The previous prime is 261123463. The next prime is 261123521. The reversal of 261123507 is 705321162.

It is a happy number.

It is not a de Polignac number, because 261123507 - 2¹⁰ = 261122483 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 (261123407) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 669 + ... + 22862.

Almost surely, 2^261123507 is an apocalyptic number.

261123507 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

261123507 is a deficient number, since it is larger than the sum of its proper divisors (131813829).

261123507 is a wasteful number, since it uses less digits than its factorization.

261123507 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23680 (or 23671 counting only the distinct ones).

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

The square root of 261123507 is about 16159.3164149973. The cubic root of 261123507 is about 639.1684406840.

Adding to 261123507 its reverse (705321162), we get a palindrome (966444669).

The spelling of 261123507 in words is "two hundred sixty-one million, one hundred twenty-three thousand, five hundred seven".