21180078 has 12 divisors (see below), whose sum is σ = 45890208. Its totient is φ = 7060020.

The previous prime is 21180073. The next prime is 21180083. The reversal of 21180078 is 87008112.

It is an interprime number because it is at equal distance from previous prime (21180073) and next prime (21180083).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21180073) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 588318 + ... + 588353.

It is an arithmetic number, because the mean of its divisors is an integer number (3824184).

Almost surely, 2^21180078 is an apocalyptic number.

21180078 is an abundant number, since it is smaller than the sum of its proper divisors (24710130).

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

21180078 is a wasteful number, since it uses less digits than its factorization.

21180078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1176679 (or 1176676 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 27.

The square root of 21180078 is about 4602.1818738507. The cubic root of 21180078 is about 276.6787798119.

The spelling of 21180078 in words is "twenty-one million, one hundred eighty thousand, seventy-eight".