21873078 has 20 divisors (see below), whose sum is σ = 49012260. Its totient is φ = 7290972.

The previous prime is 21873077. The next prime is 21873097. The reversal of 21873078 is 87037812.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21873077) 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 9 ways as a sum of consecutive naturals, for example, 67348 + ... + 67671.

It is an arithmetic number, because the mean of its divisors is an integer number (2450613).

Almost surely, 2^21873078 is an apocalyptic number.

21873078 is an abundant number, since it is smaller than the sum of its proper divisors (27139182).

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

21873078 is a wasteful number, since it uses less digits than its factorization.

21873078 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135033 (or 135024 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The square root of 21873078 is about 4676.8662585111. The cubic root of 21873078 is about 279.6640443466.

It can be divided in two parts, 2 and 1873078, that added together give a triangular number (1873080 = T₁₉₃₅).

The spelling of 21873078 in words is "twenty-one million, eight hundred seventy-three thousand, seventy-eight".