20997629 has 4 divisors (see below), whose sum is σ = 21113820. Its totient is φ = 20881440.

The previous prime is 20997619. The next prime is 20997637. The reversal of 20997629 is 92679902.

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

It can be written as a sum of positive squares in 2 ways, for example, as 765625 + 20232004 = 875^2 + 4498^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20997629 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20997629.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20997619) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57824 + ... + 58185.

It is an arithmetic number, because the mean of its divisors is an integer number (5278455).

Almost surely, 2^20997629 is an apocalyptic number.

It is an amenable number.

20997629 is a deficient number, since it is larger than the sum of its proper divisors (116191).

20997629 is a wasteful number, since it uses less digits than its factorization.

20997629 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 116190.

The product of its (nonzero) digits is 122472, while the sum is 44.

The square root of 20997629 is about 4582.3169903445. The cubic root of 20997629 is about 275.8820340581.

The spelling of 20997629 in words is "twenty million, nine hundred ninety-seven thousand, six hundred twenty-nine".