20923457 has 4 divisors (see below), whose sum is σ = 21028800. Its totient is φ = 20818116.

The previous prime is 20923429. The next prime is 20923459. The reversal of 20923457 is 75432902.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20923457 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20923459) 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 3 ways as a sum of consecutive naturals, for example, 52373 + ... + 52770.

It is an arithmetic number, because the mean of its divisors is an integer number (5257200).

Almost surely, 2^20923457 is an apocalyptic number.

It is an amenable number.

20923457 is a deficient number, since it is larger than the sum of its proper divisors (105343).

20923457 is a wasteful number, since it uses less digits than its factorization.

20923457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105342.

The product of its (nonzero) digits is 15120, while the sum is 32.

The square root of 20923457 is about 4574.2165449397. The cubic root of 20923457 is about 275.5568090245.

The spelling of 20923457 in words is "twenty million, nine hundred twenty-three thousand, four hundred fifty-seven".