261988151 has 2 divisors, whose sum is σ = 261988152. Its totient is φ = 261988150.

The previous prime is 261988141. The next prime is 261988163. The reversal of 261988151 is 151889162.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 261988151 - 2¹⁰ = 261987127 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 261988099 and 261988108.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261988141) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130994075 + 130994076.

It is an arithmetic number, because the mean of its divisors is an integer number (130994076).

Almost surely, 2^261988151 is an apocalyptic number.

261988151 is a deficient number, since it is larger than the sum of its proper divisors (1).

261988151 is an equidigital number, since it uses as much as digits as its factorization.

261988151 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34560, while the sum is 41.

The square root of 261988151 is about 16186.0480352679. The cubic root of 261988151 is about 639.8731446166.

The spelling of 261988151 in words is "two hundred sixty-one million, nine hundred eighty-eight thousand, one hundred fifty-one".