20911913 has 8 divisors (see below), whose sum is σ = 24013920. Its totient is φ = 18010080.

The previous prime is 20911909. The next prime is 20911931. The reversal of 20911913 is 31911902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20911913 - 2² = 20911909 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20911963) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49820 + ... + 50237.

It is an arithmetic number, because the mean of its divisors is an integer number (3001740).

Almost surely, 2^20911913 is an apocalyptic number.

It is an amenable number.

20911913 is a deficient number, since it is larger than the sum of its proper divisors (3102007).

20911913 is a wasteful number, since it uses less digits than its factorization.

20911913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100087.

The product of its (nonzero) digits is 486, while the sum is 26.

The square root of 20911913 is about 4572.9545154090. The cubic root of 20911913 is about 275.5061224832.

It can be divided in two parts, 2091 and 1913, that added together give a palindrome (4004).

The spelling of 20911913 in words is "twenty million, nine hundred eleven thousand, nine hundred thirteen".