20415791 has 4 divisors (see below), whose sum is σ = 22271784. Its totient is φ = 18559800.

The previous prime is 20415779. The next prime is 20415817. The reversal of 20415791 is 19751402.

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

It is a cyclic number.

It is not a de Polignac number, because 20415791 - 2²² = 16221487 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 (20415761) 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, 927980 + ... + 928001.

It is an arithmetic number, because the mean of its divisors is an integer number (5567946).

Almost surely, 2^20415791 is an apocalyptic number.

20415791 is a deficient number, since it is larger than the sum of its proper divisors (1855993).

20415791 is a wasteful number, since it uses less digits than its factorization.

20415791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1855992.

The product of its (nonzero) digits is 2520, while the sum is 29.

The square root of 20415791 is about 4518.3836711815. The cubic root of 20415791 is about 273.3099254526.

The spelling of 20415791 in words is "twenty million, four hundred fifteen thousand, seven hundred ninety-one".