1621974073 has 2 divisors, whose sum is σ = 1621974074. Its totient is φ = 1621974072.

The previous prime is 1621974071. The next prime is 1621974209. The reversal of 1621974073 is 3704791261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 944517289 + 677456784 = 30733^2 + 26028^2 .

It is an emirp because it is prime and its reverse (3704791261) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1621974073 - 2¹ = 1621974071 is a prime.

Together with 1621974071, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1621974071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810987036 + 810987037.

It is an arithmetic number, because the mean of its divisors is an integer number (810987037).

Almost surely, 2^1621974073 is an apocalyptic number.

It is an amenable number.

1621974073 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621974073 is an equidigital number, since it uses as much as digits as its factorization.

1621974073 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 63504, while the sum is 40.

The square root of 1621974073 is about 40273.7392478027. The cubic root of 1621974073 is about 1174.9371502221.

The spelling of 1621974073 in words is "one billion, six hundred twenty-one million, nine hundred seventy-four thousand, seventy-three".