20821712 has 20 divisors (see below), whose sum is σ = 40830720. Its totient is φ = 10284768.

The previous prime is 20821711. The next prime is 20821741. The reversal of 20821712 is 21712802.

It is a super-2 number, since 2×20821712² = 867087381221888, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20821711) 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, 6512 + ... + 9167.

It is an arithmetic number, because the mean of its divisors is an integer number (2041536).

Almost surely, 2^20821712 is an apocalyptic number.

It is an amenable number.

20821712 is a deficient number, since it is larger than the sum of its proper divisors (20009008).

20821712 is a wasteful number, since it uses less digits than its factorization.

20821712 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15770 (or 15764 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 23.

The square root of 20821712 is about 4563.0814150089. The cubic root of 20821712 is about 275.1094308285.

The spelling of 20821712 in words is "twenty million, eight hundred twenty-one thousand, seven hundred twelve".