243997687 has 2 divisors, whose sum is σ = 243997688. Its totient is φ = 243997686.

The previous prime is 243997669. The next prime is 243997717. The reversal of 243997687 is 786799342.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-243997687 is a prime.

It is a super-2 number, since 2×243997687² = 119069742522699938, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (243991687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 121998843 + 121998844.

It is an arithmetic number, because the mean of its divisors is an integer number (121998844).

Almost surely, 2^243997687 is an apocalyptic number.

243997687 is a deficient number, since it is larger than the sum of its proper divisors (1).

243997687 is an equidigital number, since it uses as much as digits as its factorization.

243997687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4572288, while the sum is 55.

The square root of 243997687 is about 15620.4253143120. The cubic root of 243997687 is about 624.8780024281.

The spelling of 243997687 in words is "two hundred forty-three million, nine hundred ninety-seven thousand, six hundred eighty-seven".