261564200213531 has 2 divisors, whose sum is σ = 261564200213532. Its totient is φ = 261564200213530.

The previous prime is 261564200213527. The next prime is 261564200213551. The reversal of 261564200213531 is 135312002465162.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261564200213531 - 2² = 261564200213527 is a prime.

It is a super-2 number, since 2×261564200213531² (a number of 30 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (261564200213551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130782100106765 + 130782100106766.

It is an arithmetic number, because the mean of its divisors is an integer number (130782100106766).

Almost surely, 2^{261564200213531} is an apocalyptic number.

261564200213531 is a deficient number, since it is larger than the sum of its proper divisors (1).

261564200213531 is an equidigital number, since it uses as much as digits as its factorization.

261564200213531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 259200, while the sum is 41.

Adding to 261564200213531 its reverse (135312002465162), we get a palindrome (396876202678693).

The spelling of 261564200213531 in words is "two hundred sixty-one trillion, five hundred sixty-four billion, two hundred million, two hundred thirteen thousand, five hundred thirty-one".