20978760 has 128 divisors (see below), whose sum is σ = 71746560. Its totient is φ = 4857600.

The previous prime is 20978759. The next prime is 20978761. The reversal of 20978760 is 6787902.

It is an interprime number because it is at equal distance from previous prime (20978759) and next prime (20978761).

It is a super-2 number, since 2×20978760² = 880216742275200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20978761) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 30015 + ... + 30705.

It is an arithmetic number, because the mean of its divisors is an integer number (560520).

Almost surely, 2^20978760 is an apocalyptic number.

20978760 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20978760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35873280).

20978760 is an abundant number, since it is smaller than the sum of its proper divisors (50767800).

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

20978760 is a wasteful number, since it uses less digits than its factorization.

20978760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 739 (or 735 counting only the distinct ones).

The product of its (nonzero) digits is 42336, while the sum is 39.

The square root of 20978760 is about 4580.2576346752. The cubic root of 20978760 is about 275.7993711031.

The spelling of 20978760 in words is "twenty million, nine hundred seventy-eight thousand, seven hundred sixty".