1921286657 has 2 divisors, whose sum is σ = 1921286658. Its totient is φ = 1921286656.

The previous prime is 1921286651. The next prime is 1921286677. The reversal of 1921286657 is 7566821291.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1902355456 + 18931201 = 43616^2 + 4351^2 .

It is a cyclic number.

It is not a de Polignac number, because 1921286657 - 2⁴ = 1921286641 is a prime.

It is not a weakly prime, because it can be changed into another prime (1921286651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 960643328 + 960643329.

It is an arithmetic number, because the mean of its divisors is an integer number (960643329).

Almost surely, 2^1921286657 is an apocalyptic number.

It is an amenable number.

1921286657 is a deficient number, since it is larger than the sum of its proper divisors (1).

1921286657 is an equidigital number, since it uses as much as digits as its factorization.

1921286657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 362880, while the sum is 47.

The square root of 1921286657 is about 43832.4840386670. The cubic root of 1921286657 is about 1243.1705752798.

The spelling of 1921286657 in words is "one billion, nine hundred twenty-one million, two hundred eighty-six thousand, six hundred fifty-seven".