21114978 has 32 divisors (see below), whose sum is σ = 43524096. Its totient is φ = 6825168.

The previous prime is 21114971. The next prime is 21114991. The reversal of 21114978 is 87941112.

It is not an unprimeable number, because it can be changed into a prime (21114971) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 57351 + ... + 57717.

It is an arithmetic number, because the mean of its divisors is an integer number (1360128).

Almost surely, 2^21114978 is an apocalyptic number.

21114978 is an abundant number, since it is smaller than the sum of its proper divisors (22409118).

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

21114978 is a wasteful number, since it uses less digits than its factorization.

21114978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 638.

The product of its digits is 4032, while the sum is 33.

The square root of 21114978 is about 4595.1036985034. The cubic root of 21114978 is about 276.3950182809.

The spelling of 21114978 in words is "twenty-one million, one hundred fourteen thousand, nine hundred seventy-eight".