261564031 has 2 divisors, whose sum is σ = 261564032. Its totient is φ = 261564030.

The previous prime is 261564007. The next prime is 261564049. The reversal of 261564031 is 130465162.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261564031 - 2⁵ = 261563999 is a prime.

It is a super-2 number, since 2×261564031² = 136831484625937922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261564001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130782015 + 130782016.

It is an arithmetic number, because the mean of its divisors is an integer number (130782016).

Almost surely, 2^261564031 is an apocalyptic number.

261564031 is a deficient number, since it is larger than the sum of its proper divisors (1).

261564031 is an equidigital number, since it uses as much as digits as its factorization.

261564031 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 261564031 is about 16172.9413218499. The cubic root of 261564031 is about 639.5276715206.

The spelling of 261564031 in words is "two hundred sixty-one million, five hundred sixty-four thousand, thirty-one".