16003997 has 2 divisors, whose sum is σ = 16003998. Its totient is φ = 16003996.

The previous prime is 16003991. The next prime is 16004047. The reversal of 16003997 is 79930061.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10686361 + 5317636 = 3269^2 + 2306^2 .

It is a cyclic number.

It is not a de Polignac number, because 16003997 - 2¹⁸ = 15741853 is a prime.

It is a super-2 number, since 2×16003997² = 512255839952018, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16003991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8001998 + 8001999.

It is an arithmetic number, because the mean of its divisors is an integer number (8001999).

Almost surely, 2^16003997 is an apocalyptic number.

It is an amenable number.

16003997 is a deficient number, since it is larger than the sum of its proper divisors (1).

16003997 is an equidigital number, since it uses as much as digits as its factorization.

16003997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10206, while the sum is 35.

The square root of 16003997 is about 4000.4995938008. The cubic root of 16003997 is about 252.0051911671.

The spelling of 16003997 in words is "sixteen million, three thousand, nine hundred ninety-seven".