20997984 has 48 divisors (see below), whose sum is σ = 62995968. Its totient is φ = 5999232.

The previous prime is 20997973. The next prime is 20997989. The reversal of 20997984 is 48979902.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20997989) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14952 + ... + 16295.

It is an arithmetic number, because the mean of its divisors is an integer number (1312416).

Almost surely, 2^20997984 is an apocalyptic number.

20997984 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

20997984 is an abundant number, since it is smaller than the sum of its proper divisors (41997984).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20997984 is a wasteful number, since it uses less digits than its factorization.

20997984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31267 (or 31259 counting only the distinct ones).

The product of its (nonzero) digits is 326592, while the sum is 48.

The square root of 20997984 is about 4582.3557260431. The cubic root of 20997984 is about 275.8835887982.

The spelling of 20997984 in words is "twenty million, nine hundred ninety-seven thousand, nine hundred eighty-four".