21636078 has 32 divisors (see below), whose sum is σ = 45204480. Its totient is φ = 6895680.

The previous prime is 21636073. The next prime is 21636089. The reversal of 21636078 is 87063612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21636073) 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 15 ways as a sum of consecutive naturals, for example, 15901 + ... + 17207.

It is an arithmetic number, because the mean of its divisors is an integer number (1412640).

Almost surely, 2^21636078 is an apocalyptic number.

21636078 is an abundant number, since it is smaller than the sum of its proper divisors (23568402).

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

21636078 is a wasteful number, since it uses less digits than its factorization.

21636078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1432.

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 21636078 is about 4651.4597708676. The cubic root of 21636078 is about 278.6502986222.

The spelling of 21636078 in words is "twenty-one million, six hundred thirty-six thousand, seventy-eight".