1991497340 has 24 divisors (see below), whose sum is σ = 4779593952. Its totient is φ = 682799040.

The previous prime is 1991497337. The next prime is 1991497357. The reversal of 1991497340 is 437941991.

1991497340 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (47) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7112351 + ... + 7112630.

It is an arithmetic number, because the mean of its divisors is an integer number (199149748).

Almost surely, 2^1991497340 is an apocalyptic number.

1991497340 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1991497340 is an abundant number, since it is smaller than the sum of its proper divisors (2788096612).

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

1991497340 is a wasteful number, since it uses less digits than its factorization.

1991497340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14224997 (or 14224995 counting only the distinct ones).

The product of its (nonzero) digits is 244944, while the sum is 47.

The square root of 1991497340 is about 44626.1956702563. The cubic root of 1991497340 is about 1258.1330670086.

The spelling of 1991497340 in words is "one billion, nine hundred ninety-one million, four hundred ninety-seven thousand, three hundred forty".