781126531 has 2 divisors, whose sum is σ = 781126532. Its totient is φ = 781126530.

The previous prime is 781126477. The next prime is 781126609. The reversal of 781126531 is 135621187.

It is a happy number.

781126531 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 781126531 - 2²¹ = 779029379 is a prime.

It is a super-3 number, since 3×781126531³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (781126231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 390563265 + 390563266.

It is an arithmetic number, because the mean of its divisors is an integer number (390563266).

Almost surely, 2^781126531 is an apocalyptic number.

781126531 is a deficient number, since it is larger than the sum of its proper divisors (1).

781126531 is an equidigital number, since it uses as much as digits as its factorization.

781126531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10080, while the sum is 34.

The square root of 781126531 is about 27948.6409508584. The cubic root of 781126531 is about 920.9593533108.

It can be divided in two parts, 781 and 126531, that multiplied together give a triangular number (98820711 = T₁₄₀₅₈).

The spelling of 781126531 in words is "seven hundred eighty-one million, one hundred twenty-six thousand, five hundred thirty-one".