261278503 has 4 divisors (see below), whose sum is σ = 263032200. Its totient is φ = 259524808.

The previous prime is 261278489. The next prime is 261278531. The reversal of 261278503 is 305872162.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261278503 is a prime.

It is a super-2 number, since 2×261278503² = 136532912259842018, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261278543) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 876625 + ... + 876922.

It is an arithmetic number, because the mean of its divisors is an integer number (65758050).

Almost surely, 2^261278503 is an apocalyptic number.

261278503 is a deficient number, since it is larger than the sum of its proper divisors (1753697).

261278503 is a wasteful number, since it uses less digits than its factorization.

261278503 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1753696.

The product of its (nonzero) digits is 20160, while the sum is 34.

The square root of 261278503 is about 16164.1115747201. Note that the first 3 decimals coincide. The cubic root of 261278503 is about 639.2948801580.

The spelling of 261278503 in words is "two hundred sixty-one million, two hundred seventy-eight thousand, five hundred three".