20947457 has 8 divisors (see below), whose sum is σ = 22123584. Its totient is φ = 19793488.

The previous prime is 20947429. The next prime is 20947469. The reversal of 20947457 is 75474902.

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

It is a cyclic number.

It is not a de Polignac number, because 20947457 - 2⁶ = 20947393 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 20947457.

It is not an unprimeable number, because it can be changed into a prime (20947427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3578 + ... + 7395.

It is an arithmetic number, because the mean of its divisors is an integer number (2765448).

Almost surely, 2^20947457 is an apocalyptic number.

It is an amenable number.

20947457 is a deficient number, since it is larger than the sum of its proper divisors (1176127).

20947457 is a wasteful number, since it uses less digits than its factorization.

20947457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11079.

The product of its (nonzero) digits is 70560, while the sum is 38.

The square root of 20947457 is about 4576.8391931550. The cubic root of 20947457 is about 275.6621268094.

The spelling of 20947457 in words is "twenty million, nine hundred forty-seven thousand, four hundred fifty-seven".