20912691 has 8 divisors (see below), whose sum is σ = 28340944. Its totient is φ = 13713120.

The previous prime is 20912677. The next prime is 20912707. The reversal of 20912691 is 19621902.

It is a happy number.

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

It is not a de Polignac number, because 20912691 - 2⁶ = 20912627 is a prime.

It is a super-2 number, since 2×20912691² = 874681289722962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20912611) 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, 56956 + ... + 57321.

It is an arithmetic number, because the mean of its divisors is an integer number (3542618).

Almost surely, 2^20912691 is an apocalyptic number.

20912691 is a deficient number, since it is larger than the sum of its proper divisors (7428253).

20912691 is a wasteful number, since it uses less digits than its factorization.

20912691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114341.

The product of its (nonzero) digits is 1944, while the sum is 30.

The square root of 20912691 is about 4573.0395799730. The cubic root of 20912691 is about 275.5095390542.

The spelling of 20912691 in words is "twenty million, nine hundred twelve thousand, six hundred ninety-one".