997603781 has 2 divisors, whose sum is σ = 997603782. Its totient is φ = 997603780.

The previous prime is 997603753. The next prime is 997603787. The reversal of 997603781 is 187306799.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 770950756 + 226653025 = 27766^2 + 15055^2 .

It is a cyclic number.

It is not a de Polignac number, because 997603781 - 2¹⁴ = 997587397 is a prime.

It is a super-2 number, since 2×997603781² = 1990426607730991922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (997603787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 498801890 + 498801891.

It is an arithmetic number, because the mean of its divisors is an integer number (498801891).

Almost surely, 2^997603781 is an apocalyptic number.

It is an amenable number.

997603781 is a deficient number, since it is larger than the sum of its proper divisors (1).

997603781 is an equidigital number, since it uses as much as digits as its factorization.

997603781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 571536, while the sum is 50.

The square root of 997603781 is about 31584.8663286708. The cubic root of 997603781 is about 999.2006214976.

The spelling of 997603781 in words is "nine hundred ninety-seven million, six hundred three thousand, seven hundred eighty-one".