681533987 has 2 divisors, whose sum is σ = 681533988. Its totient is φ = 681533986.

The previous prime is 681533929. The next prime is 681534001. The reversal of 681533987 is 789335186.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 681533987 - 2¹⁰ = 681532963 is a prime.

It is a super-2 number, since 2×681533987² = 928977150872232338, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (681533917) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340766993 + 340766994.

It is an arithmetic number, because the mean of its divisors is an integer number (340766994).

Almost surely, 2^681533987 is an apocalyptic number.

681533987 is a deficient number, since it is larger than the sum of its proper divisors (1).

681533987 is an equidigital number, since it uses as much as digits as its factorization.

681533987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1088640, while the sum is 50.

The square root of 681533987 is about 26106.2059097066. The cubic root of 681533987 is about 880.0266809231.

The spelling of 681533987 in words is "six hundred eighty-one million, five hundred thirty-three thousand, nine hundred eighty-seven".