191993640 has 64 divisors (see below), whose sum is σ = 576892800. Its totient is φ = 51117312.

The previous prime is 191993623. The next prime is 191993663. The reversal of 191993640 is 46399191.

191993640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 191993592 and 191993601.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 144901 + ... + 146219.

It is an arithmetic number, because the mean of its divisors is an integer number (9013950).

Almost surely, 2^191993640 is an apocalyptic number.

191993640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

191993640 is an abundant number, since it is smaller than the sum of its proper divisors (384899160).

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

191993640 is a wasteful number, since it uses less digits than its factorization.

191993640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2546 (or 2542 counting only the distinct ones).

The product of its (nonzero) digits is 52488, while the sum is 42.

The square root of 191993640 is about 13856.1769619185. The cubic root of 191993640 is about 576.8934581170.

It can be divided in two parts, 1919 and 93640, that added together give a palindrome (95559).

The spelling of 191993640 in words is "one hundred ninety-one million, nine hundred ninety-three thousand, six hundred forty".