281512661 has 2 divisors, whose sum is σ = 281512662. Its totient is φ = 281512660.

The previous prime is 281512633. The next prime is 281512681. The reversal of 281512661 is 166215182.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 212722225 + 68790436 = 14585^2 + 8294^2 .

It is a cyclic number.

It is not a de Polignac number, because 281512661 - 2⁶ = 281512597 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (281512631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 140756330 + 140756331.

It is an arithmetic number, because the mean of its divisors is an integer number (140756331).

Almost surely, 2^281512661 is an apocalyptic number.

It is an amenable number.

281512661 is a deficient number, since it is larger than the sum of its proper divisors (1).

281512661 is an equidigital number, since it uses as much as digits as its factorization.

281512661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5760, while the sum is 32.

The square root of 281512661 is about 16778.3390417526. The cubic root of 281512661 is about 655.3892455527.

The spelling of 281512661 in words is "two hundred eighty-one million, five hundred twelve thousand, six hundred sixty-one".