21980786 has 8 divisors (see below), whose sum is σ = 33044700. Its totient is φ = 10965888.

The previous prime is 21980771. The next prime is 21980789. The reversal of 21980786 is 68708912.

It can be written as a sum of positive squares in 2 ways, for example, as 21114025 + 866761 = 4595^2 + 931^2 .

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 (21980789) 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, 11111 + ... + 12938.

Almost surely, 2^21980786 is an apocalyptic number.

21980786 is a deficient number, since it is larger than the sum of its proper divisors (11063914).

21980786 is a wasteful number, since it uses less digits than its factorization.

21980786 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24508.

The product of its (nonzero) digits is 48384, while the sum is 41.

The square root of 21980786 is about 4688.3670931359. The cubic root of 21980786 is about 280.1223359977.

The spelling of 21980786 in words is "twenty-one million, nine hundred eighty thousand, seven hundred eighty-six".