20688970 has 8 divisors (see below), whose sum is σ = 37240164. Its totient is φ = 8275584.

The previous prime is 20688959. The next prime is 20688973. The reversal of 20688970 is 7988602.

It can be written as a sum of positive squares in 2 ways, for example, as 19686969 + 1002001 = 4437^2 + 1001^2 .

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 (20688973) 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, 1034439 + ... + 1034458.

Almost surely, 2^20688970 is an apocalyptic number.

20688970 is a deficient number, since it is larger than the sum of its proper divisors (16551194).

20688970 is a wasteful number, since it uses less digits than its factorization.

20688970 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2068904.

The product of its (nonzero) digits is 48384, while the sum is 40.

The square root of 20688970 is about 4548.5129438092. The cubic root of 20688970 is about 274.5235607175.

The spelling of 20688970 in words is "twenty million, six hundred eighty-eight thousand, nine hundred seventy".