21527978 has 8 divisors (see below), whose sum is σ = 32313600. Its totient is φ = 10756780.

The previous prime is 21527953. The next prime is 21527983. The reversal of 21527978 is 87972512.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1673 + ... + 6771.

It is an arithmetic number, because the mean of its divisors is an integer number (4039200).

Almost surely, 2^21527978 is an apocalyptic number.

21527978 is a deficient number, since it is larger than the sum of its proper divisors (10785622).

21527978 is a wasteful number, since it uses less digits than its factorization.

21527978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7212.

The product of its digits is 70560, while the sum is 41.

The square root of 21527978 is about 4639.8252122251. The cubic root of 21527978 is about 278.1854515401.

The spelling of 21527978 in words is "twenty-one million, five hundred twenty-seven thousand, nine hundred seventy-eight".