1921273687 has 2 divisors, whose sum is σ = 1921273688. Its totient is φ = 1921273686.

The previous prime is 1921273657. The next prime is 1921273769. The reversal of 1921273687 is 7863721291.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1921273687 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1921273637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 960636843 + 960636844.

It is an arithmetic number, because the mean of its divisors is an integer number (960636844).

Almost surely, 2^1921273687 is an apocalyptic number.

1921273687 is a deficient number, since it is larger than the sum of its proper divisors (1).

1921273687 is an equidigital number, since it uses as much as digits as its factorization.

1921273687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 254016, while the sum is 46.

The square root of 1921273687 is about 43832.3360887827. The cubic root of 1921273687 is about 1243.1677778560.

The spelling of 1921273687 in words is "one billion, nine hundred twenty-one million, two hundred seventy-three thousand, six hundred eighty-seven".