20293991 has 4 divisors (see below), whose sum is σ = 20307672. Its totient is φ = 20280312.

The previous prime is 20293963. The next prime is 20294003. The reversal of 20293991 is 19939202.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20293991 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20293921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4301 + ... + 7686.

It is an arithmetic number, because the mean of its divisors is an integer number (5076918).

Almost surely, 2^20293991 is an apocalyptic number.

20293991 is a deficient number, since it is larger than the sum of its proper divisors (13681).

20293991 is a wasteful number, since it uses less digits than its factorization.

20293991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13680.

The product of its (nonzero) digits is 8748, while the sum is 35.

The square root of 20293991 is about 4504.8852371620. The cubic root of 20293991 is about 272.7653213616.

The spelling of 20293991 in words is "twenty million, two hundred ninety-three thousand, nine hundred ninety-one".