191981651 has 2 divisors, whose sum is σ = 191981652. Its totient is φ = 191981650.

The previous prime is 191981611. The next prime is 191981753. The reversal of 191981651 is 156189191.

It is a happy number.

191981651 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-191981651 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 191981599 and 191981608.

It is not a weakly prime, because it can be changed into another prime (191981611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95990825 + 95990826.

It is an arithmetic number, because the mean of its divisors is an integer number (95990826).

Almost surely, 2^191981651 is an apocalyptic number.

191981651 is a deficient number, since it is larger than the sum of its proper divisors (1).

191981651 is an equidigital number, since it uses as much as digits as its factorization.

191981651 is an evil number, because the sum of its binary digits is even.

The product of its digits is 19440, while the sum is 41.

The square root of 191981651 is about 13855.7443322255. The cubic root of 191981651 is about 576.8814498727.

The spelling of 191981651 in words is "one hundred ninety-one million, nine hundred eighty-one thousand, six hundred fifty-one".