1642639541 has 2 divisors, whose sum is σ = 1642639542. Its totient is φ = 1642639540.

The previous prime is 1642639423. The next prime is 1642639543. The reversal of 1642639541 is 1459362461.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1174090225 + 468549316 = 34265^2 + 21646^2 .

It is a cyclic number.

It is not a de Polignac number, because 1642639541 - 2³⁰ = 568897717 is a prime.

Together with 1642639543, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1642639543) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 821319770 + 821319771.

It is an arithmetic number, because the mean of its divisors is an integer number (821319771).

Almost surely, 2^1642639541 is an apocalyptic number.

It is an amenable number.

1642639541 is a deficient number, since it is larger than the sum of its proper divisors (1).

1642639541 is an equidigital number, since it uses as much as digits as its factorization.

1642639541 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 155520, while the sum is 41.

The square root of 1642639541 is about 40529.4897697960. The cubic root of 1642639541 is about 1179.9060398707.

The spelling of 1642639541 in words is "one billion, six hundred forty-two million, six hundred thirty-nine thousand, five hundred forty-one".