20715780 has 24 divisors (see below), whose sum is σ = 58004352. Its totient is φ = 5524192.

The previous prime is 20715763. The next prime is 20715787. The reversal of 20715780 is 8751702.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (20715787) 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, 172572 + ... + 172691.

It is an arithmetic number, because the mean of its divisors is an integer number (2416848).

Almost surely, 2^20715780 is an apocalyptic number.

20715780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20715780 is an abundant number, since it is smaller than the sum of its proper divisors (37288572).

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

20715780 is a wasteful number, since it uses less digits than its factorization.

20715780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 345275 (or 345273 counting only the distinct ones).

The product of its (nonzero) digits is 3920, while the sum is 30.

The square root of 20715780 is about 4551.4591067041. The cubic root of 20715780 is about 274.6420908615.

The spelling of 20715780 in words is "twenty million, seven hundred fifteen thousand, seven hundred eighty".