20978496 has 252 divisors, whose sum is σ = 77293216. Its totient is φ = 5322240.

The previous prime is 20978483. The next prime is 20978533. The reversal of 20978496 is 69487902.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (252).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 487851 + ... + 487893.

Almost surely, 2^20978496 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20978496, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38646608).

20978496 is an abundant number, since it is smaller than the sum of its proper divisors (56314720).

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

20978496 is a wasteful number, since it uses less digits than its factorization.

20978496 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90 (or 66 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 45.

The square root of 20978496 is about 4580.2288152449. The cubic root of 20978496 is about 275.7982141975.

The spelling of 20978496 in words is "twenty million, nine hundred seventy-eight thousand, four hundred ninety-six".