20820970 has 8 divisors (see below), whose sum is σ = 37477764. Its totient is φ = 8328384.

The previous prime is 20820967. The next prime is 20820977. The reversal of 20820970 is 7902802.

It is a Cunningham number, because it is equal to 4563²+1.

It can be written as a sum of positive squares in 2 ways, for example, as 20820969 + 1 = 4563^2 + 1^2 .

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

It is not an unprimeable number, because it can be changed into a prime (20820977) 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, 1041039 + ... + 1041058.

Almost surely, 2^20820970 is an apocalyptic number.

20820970 is a deficient number, since it is larger than the sum of its proper divisors (16656794).

20820970 is a wasteful number, since it uses less digits than its factorization.

20820970 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2082104.

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 20820970 is about 4563.0001095770. Note that the first 3 decimals coincide. The cubic root of 20820970 is about 275.1061628676.

The spelling of 20820970 in words is "twenty million, eight hundred twenty thousand, nine hundred seventy".