20657984 has 14 divisors (see below), whose sum is σ = 40993314. Its totient is φ = 10328960.

The previous prime is 20657983. The next prime is 20657999. The reversal of 20657984 is 48975602.

It can be written as a sum of positive squares in only one way, i.e., 13897984 + 6760000 = 3728^2 + 2600^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20657983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161327 + ... + 161454.

Almost surely, 2^20657984 is an apocalyptic number.

It is an amenable number.

20657984 is a deficient number, since it is larger than the sum of its proper divisors (20335330).

20657984 is an equidigital number, since it uses as much as digits as its factorization.

20657984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322793 (or 322783 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 41.

The square root of 20657984 is about 4545.1054993256. The cubic root of 20657984 is about 274.3864403537.

The spelling of 20657984 in words is "twenty million, six hundred fifty-seven thousand, nine hundred eighty-four".