20989810 has 8 divisors (see below), whose sum is σ = 37781676. Its totient is φ = 8395920.

The previous prime is 20989807. The next prime is 20989847. The reversal of 20989810 is 1898902.

It can be written as a sum of positive squares in 2 ways, for example, as 20007729 + 982081 = 4473^2 + 991^2 .

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

It is a super-2 number, since 2×20989810² = 881144247672200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20989810.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1049481 + ... + 1049500.

Almost surely, 2^20989810 is an apocalyptic number.

20989810 is a deficient number, since it is larger than the sum of its proper divisors (16791866).

20989810 is a wasteful number, since it uses less digits than its factorization.

20989810 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2098988.

The product of its (nonzero) digits is 10368, while the sum is 37.

The square root of 20989810 is about 4581.4637398980. The cubic root of 20989810 is about 275.8477859146.

The spelling of 20989810 in words is "twenty million, nine hundred eighty-nine thousand, eight hundred ten".