1620987541 has 2 divisors, whose sum is σ = 1620987542. Its totient is φ = 1620987540.

The previous prime is 1620987517. The next prime is 1620987569. The reversal of 1620987541 is 1457890261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1378562641 + 242424900 = 37129^2 + 15570^2 .

It is an emirp because it is prime and its reverse (1457890261) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1620987541 - 2¹¹ = 1620985493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1620987041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810493770 + 810493771.

It is an arithmetic number, because the mean of its divisors is an integer number (810493771).

Almost surely, 2^1620987541 is an apocalyptic number.

It is an amenable number.

1620987541 is a deficient number, since it is larger than the sum of its proper divisors (1).

1620987541 is an equidigital number, since it uses as much as digits as its factorization.

1620987541 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 120960, while the sum is 43.

The square root of 1620987541 is about 40261.4895526730. The cubic root of 1620987541 is about 1174.6988915476.

The spelling of 1620987541 in words is "one billion, six hundred twenty million, nine hundred eighty-seven thousand, five hundred forty-one".