20766021 has 4 divisors (see below), whose sum is σ = 27688032. Its totient is φ = 13844012.

The previous prime is 20766007. The next prime is 20766023. The reversal of 20766021 is 12066702.

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 not a de Polignac number, because 20766021 - 2⁶ = 20765957 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20765982 and 20766000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20766023) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3461001 + ... + 3461006.

It is an arithmetic number, because the mean of its divisors is an integer number (6922008).

Almost surely, 2^20766021 is an apocalyptic number.

It is an amenable number.

20766021 is a deficient number, since it is larger than the sum of its proper divisors (6922011).

20766021 is an equidigital number, since it uses as much as digits as its factorization.

20766021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6922010.

The product of its (nonzero) digits is 1008, while the sum is 24.

The square root of 20766021 is about 4556.9749834731. The cubic root of 20766021 is about 274.8639370984.

The spelling of 20766021 in words is "twenty million, seven hundred sixty-six thousand, twenty-one".