261663533 has 2 divisors, whose sum is σ = 261663534. Its totient is φ = 261663532.

The previous prime is 261663509. The next prime is 261663539. The reversal of 261663533 is 335366162.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 207302404 + 54361129 = 14398^2 + 7373^2 .

It is a cyclic number.

It is not a de Polignac number, because 261663533 - 2⁸ = 261663277 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 261663493 and 261663502.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261663539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130831766 + 130831767.

It is an arithmetic number, because the mean of its divisors is an integer number (130831767).

Almost surely, 2^261663533 is an apocalyptic number.

It is an amenable number.

261663533 is a deficient number, since it is larger than the sum of its proper divisors (1).

261663533 is an equidigital number, since it uses as much as digits as its factorization.

261663533 is an evil number, because the sum of its binary digits is even.

The product of its digits is 58320, while the sum is 35.

The square root of 261663533 is about 16176.0172168553. The cubic root of 261663533 is about 639.6087558282.

The spelling of 261663533 in words is "two hundred sixty-one million, six hundred sixty-three thousand, five hundred thirty-three".