191325821 has 2 divisors, whose sum is σ = 191325822. Its totient is φ = 191325820.

The previous prime is 191325817. The next prime is 191325833. The reversal of 191325821 is 128523191.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 160300921 + 31024900 = 12661^2 + 5570^2 .

It is a cyclic number.

It is not a de Polignac number, because 191325821 - 2² = 191325817 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191325221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95662910 + 95662911.

It is an arithmetic number, because the mean of its divisors is an integer number (95662911).

Almost surely, 2^191325821 is an apocalyptic number.

It is an amenable number.

191325821 is a deficient number, since it is larger than the sum of its proper divisors (1).

191325821 is an equidigital number, since it uses as much as digits as its factorization.

191325821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4320, while the sum is 32.

The square root of 191325821 is about 13832.0577283353. The cubic root of 191325821 is about 576.2238040488.

The spelling of 191325821 in words is "one hundred ninety-one million, three hundred twenty-five thousand, eight hundred twenty-one".