20191291 has 4 divisors (see below), whose sum is σ = 21379032. Its totient is φ = 19003552.

The previous prime is 20191277. The next prime is 20191333. The reversal of 20191291 is 19219102.

It is a semiprime because it is the product of two primes.

It is a de Polignac number, because none of the positive numbers 2^k-20191291 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20191231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 593845 + ... + 593878.

It is an arithmetic number, because the mean of its divisors is an integer number (5344758).

Almost surely, 2^20191291 is an apocalyptic number.

20191291 is a deficient number, since it is larger than the sum of its proper divisors (1187741).

20191291 is a wasteful number, since it uses less digits than its factorization.

20191291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1187740.

The product of its (nonzero) digits is 324, while the sum is 25.

The square root of 20191291 is about 4493.4720428640. The cubic root of 20191291 is about 272.3044232546.

The spelling of 20191291 in words is "twenty million, one hundred ninety-one thousand, two hundred ninety-one".