20691147 has 16 divisors (see below), whose sum is σ = 28304640. Its totient is φ = 13439712.

The previous prime is 20691137. The next prime is 20691149. The reversal of 20691147 is 74119602.

It is a happy number.

It is not a de Polignac number, because 20691147 - 2⁴ = 20691131 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20691149) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28098 + ... + 28824.

It is an arithmetic number, because the mean of its divisors is an integer number (1769040).

Almost surely, 2^20691147 is an apocalyptic number.

20691147 is a deficient number, since it is larger than the sum of its proper divisors (7613493).

20691147 is a wasteful number, since it uses less digits than its factorization.

20691147 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 962.

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 20691147 is about 4548.7522464957. The cubic root of 20691147 is about 274.5331893075.

The spelling of 20691147 in words is "twenty million, six hundred ninety-one thousand, one hundred forty-seven".