191421820 has 12 divisors (see below), whose sum is σ = 401985864. Its totient is φ = 76568720.

The previous prime is 191421817. The next prime is 191421829. The reversal of 191421820 is 28124191.

It is a super-2 number, since 2×191421820² = 73284626344224800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191421829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4785526 + ... + 4785565.

It is an arithmetic number, because the mean of its divisors is an integer number (33498822).

Almost surely, 2^191421820 is an apocalyptic number.

191421820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

191421820 is an abundant number, since it is smaller than the sum of its proper divisors (210564044).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

191421820 is a wasteful number, since it uses less digits than its factorization.

191421820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9571100 (or 9571098 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 28.

The square root of 191421820 is about 13835.5274565157. The cubic root of 191421820 is about 576.3201626399.

The spelling of 191421820 in words is "one hundred ninety-one million, four hundred twenty-one thousand, eight hundred twenty".