1921421407 has 2 divisors, whose sum is σ = 1921421408. Its totient is φ = 1921421406.

The previous prime is 1921421389. The next prime is 1921421459. The reversal of 1921421407 is 7041241291.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1921421407 - 2⁷ = 1921421279 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1921421497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 960710703 + 960710704.

It is an arithmetic number, because the mean of its divisors is an integer number (960710704).

Almost surely, 2^1921421407 is an apocalyptic number.

1921421407 is a deficient number, since it is larger than the sum of its proper divisors (1).

1921421407 is an equidigital number, since it uses as much as digits as its factorization.

1921421407 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 1921421407 is about 43834.0211137422. The cubic root of 1921421407 is about 1243.1996379773.

Adding to 1921421407 its reverse (7041241291), we get a palindrome (8962662698).

The spelling of 1921421407 in words is "one billion, nine hundred twenty-one million, four hundred twenty-one thousand, four hundred seven".