196571821 has 2 divisors, whose sum is σ = 196571822. Its totient is φ = 196571820.

The previous prime is 196571801. The next prime is 196571857. The reversal of 196571821 is 128175691.

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., 192515625 + 4056196 = 13875^2 + 2014^2 .

It is a cyclic number.

It is not a de Polignac number, because 196571821 - 2¹⁵ = 196539053 is a prime.

It is a super-2 number, since 2×196571821² = 77280961622512082, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (196571801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 98285910 + 98285911.

It is an arithmetic number, because the mean of its divisors is an integer number (98285911).

Almost surely, 2^196571821 is an apocalyptic number.

It is an amenable number.

196571821 is a deficient number, since it is larger than the sum of its proper divisors (1).

196571821 is an equidigital number, since it uses as much as digits as its factorization.

196571821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 30240, while the sum is 40.

The square root of 196571821 is about 14020.4073050679. The cubic root of 196571821 is about 581.4429204144.

The spelling of 196571821 in words is "one hundred ninety-six million, five hundred seventy-one thousand, eight hundred twenty-one".