1642791421 has 2 divisors, whose sum is σ = 1642791422. Its totient is φ = 1642791420.

The previous prime is 1642791389. The next prime is 1642791439. The reversal of 1642791421 is 1241972461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1111488921 + 531302500 = 33339^2 + 23050^2 .

It is an emirp because it is prime and its reverse (1241972461) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1642791421 - 2⁵ = 1642791389 is a prime.

It is a super-2 number, since 2×1642791421² = 5397527305822398482, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1642794421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 821395710 + 821395711.

It is an arithmetic number, because the mean of its divisors is an integer number (821395711).

Almost surely, 2^1642791421 is an apocalyptic number.

It is an amenable number.

1642791421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1642791421 is an equidigital number, since it uses as much as digits as its factorization.

1642791421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 24192, while the sum is 37.

The square root of 1642791421 is about 40531.3634238968. The cubic root of 1642791421 is about 1179.9424038248.

The spelling of 1642791421 in words is "one billion, six hundred forty-two million, seven hundred ninety-one thousand, four hundred twenty-one".