1282687921 has 2 divisors, whose sum is σ = 1282687922. Its totient is φ = 1282687920.

The previous prime is 1282687883. The next prime is 1282687963. The reversal of 1282687921 is 1297862821.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 748569600 + 534118321 = 27360^2 + 23111^2 .

It is an emirp because it is prime and its reverse (1297862821) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1282687921 - 2²⁵ = 1249133489 is a prime.

It is not a weakly prime, because it can be changed into another prime (1282667921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 641343960 + 641343961.

It is an arithmetic number, because the mean of its divisors is an integer number (641343961).

Almost surely, 2^1282687921 is an apocalyptic number.

It is an amenable number.

1282687921 is a deficient number, since it is larger than the sum of its proper divisors (1).

1282687921 is an equidigital number, since it uses as much as digits as its factorization.

1282687921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 193536, while the sum is 46.

The square root of 1282687921 is about 35814.6327776790. The cubic root of 1282687921 is about 1086.5265298584.

The spelling of 1282687921 in words is "one billion, two hundred eighty-two million, six hundred eighty-seven thousand, nine hundred twenty-one".