1997383021 has 2 divisors, whose sum is σ = 1997383022. Its totient is φ = 1997383020.

The previous prime is 1997382971. The next prime is 1997383027. The reversal of 1997383021 is 1203837991.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1908816100 + 88566921 = 43690^2 + 9411^2 .

It is an emirp because it is prime and its reverse (1203837991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1997383021 - 2⁹ = 1997382509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1997383027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 998691510 + 998691511.

It is an arithmetic number, because the mean of its divisors is an integer number (998691511).

Almost surely, 2^1997383021 is an apocalyptic number.

It is an amenable number.

1997383021 is a deficient number, since it is larger than the sum of its proper divisors (1).

1997383021 is an equidigital number, since it uses as much as digits as its factorization.

1997383021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 81648, while the sum is 43.

The square root of 1997383021 is about 44692.0912578501. The cubic root of 1997383021 is about 1259.3712788804.

The spelling of 1997383021 in words is "one billion, nine hundred ninety-seven million, three hundred eighty-three thousand, twenty-one".