20978370 has 144 divisors (see below), whose sum is σ = 65302848. Its totient is φ = 4656960.

The previous prime is 20978359. The next prime is 20978383. The reversal of 20978370 is 7387902.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 295435 + ... + 295505.

It is an arithmetic number, because the mean of its divisors is an integer number (453492).

Almost surely, 2^20978370 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20978370, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32651424).

20978370 is an abundant number, since it is smaller than the sum of its proper divisors (44324478).

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

20978370 is a wasteful number, since it uses less digits than its factorization.

20978370 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165 (or 155 counting only the distinct ones).

The product of its (nonzero) digits is 21168, while the sum is 36.

The square root of 20978370 is about 4580.2150604529. The cubic root of 20978370 is about 275.7976620345.

The spelling of 20978370 in words is "twenty million, nine hundred seventy-eight thousand, three hundred seventy".