21780514 has 8 divisors (see below), whose sum is σ = 37338048. Its totient is φ = 9334500.

The previous prime is 21780511. The next prime is 21780523. The reversal of 21780514 is 41508712.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21780511) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 777862 + ... + 777889.

It is an arithmetic number, because the mean of its divisors is an integer number (4667256).

Almost surely, 2^21780514 is an apocalyptic number.

21780514 is a deficient number, since it is larger than the sum of its proper divisors (15557534).

21780514 is a wasteful number, since it uses less digits than its factorization.

21780514 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1555760.

The product of its (nonzero) digits is 2240, while the sum is 28.

The square root of 21780514 is about 4666.9598241253. The cubic root of 21780514 is about 279.2689860129.

The spelling of 21780514 in words is "twenty-one million, seven hundred eighty thousand, five hundred fourteen".