21378082 has 16 divisors (see below), whose sum is σ = 35929152. Its totient is φ = 9454320.

The previous prime is 21378079. The next prime is 21378083. The reversal of 21378082 is 28087312.

It is not an unprimeable number, because it can be changed into a prime (21378083) 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, 12318 + ... + 13945.

It is an arithmetic number, because the mean of its divisors is an integer number (2245572).

Almost surely, 2^21378082 is an apocalyptic number.

21378082 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21378082 is a deficient number, since it is larger than the sum of its proper divisors (14551070).

21378082 is a wasteful number, since it uses less digits than its factorization.

21378082 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26313.

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 21378082 is about 4623.6438011594. The cubic root of 21378082 is about 277.5382930139.

The spelling of 21378082 in words is "twenty-one million, three hundred seventy-eight thousand, eighty-two".