21078063 has 24 divisors (see below), whose sum is σ = 31868928. Its totient is φ = 13920984.

The previous prime is 21078053. The next prime is 21078067. The reversal of 21078063 is 36087012.

It is not a de Polignac number, because 21078063 - 2¹² = 21073967 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21078067) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 30520 + ... + 31202.

It is an arithmetic number, because the mean of its divisors is an integer number (1327872).

Almost surely, 2^21078063 is an apocalyptic number.

21078063 is a deficient number, since it is larger than the sum of its proper divisors (10790865).

21078063 is an equidigital number, since it uses as much as digits as its factorization.

21078063 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 825 (or 813 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 21078063 is about 4591.0851658404. The cubic root of 21078063 is about 276.2338518983.

The spelling of 21078063 in words is "twenty-one million, seventy-eight thousand, sixty-three".