20691895 has 16 divisors (see below), whose sum is σ = 28531008. Its totient is φ = 14112000.

The previous prime is 20691887. The next prime is 20691919. The reversal of 20691895 is 59819602.

It is not a de Polignac number, because 20691895 - 2³ = 20691887 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5395 + ... + 8395.

It is an arithmetic number, because the mean of its divisors is an integer number (1783188).

Almost surely, 2^20691895 is an apocalyptic number.

20691895 is a deficient number, since it is larger than the sum of its proper divisors (7839113).

20691895 is a wasteful number, since it uses less digits than its factorization.

20691895 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3210.

The product of its (nonzero) digits is 38880, while the sum is 40.

The square root of 20691895 is about 4548.8344661023. The cubic root of 20691895 is about 274.5364974591.

The spelling of 20691895 in words is "twenty million, six hundred ninety-one thousand, eight hundred ninety-five".