1620542149 has 2 divisors, whose sum is σ = 1620542150. Its totient is φ = 1620542148.

The previous prime is 1620542137. The next prime is 1620542207. The reversal of 1620542149 is 9412450261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 960566049 + 659976100 = 30993^2 + 25690^2 .

It is a cyclic number.

It is not a de Polignac number, because 1620542149 - 2²³ = 1612153541 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1620540149) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810271074 + 810271075.

It is an arithmetic number, because the mean of its divisors is an integer number (810271075).

Almost surely, 2^1620542149 is an apocalyptic number.

It is an amenable number.

1620542149 is a deficient number, since it is larger than the sum of its proper divisors (1).

1620542149 is an equidigital number, since it uses as much as digits as its factorization.

1620542149 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 1620542149 is about 40255.9579317149. The cubic root of 1620542149 is about 1174.5912926504.

The spelling of 1620542149 in words is "one billion, six hundred twenty million, five hundred forty-two thousand, one hundred forty-nine".