21378830 has 16 divisors (see below), whose sum is σ = 41980464. Its totient is φ = 7774080.

The previous prime is 21378817. The next prime is 21378883. The reversal of 21378830 is 3887312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 97067 + ... + 97286.

It is an arithmetic number, because the mean of its divisors is an integer number (2623779).

Almost surely, 2^21378830 is an apocalyptic number.

21378830 is a deficient number, since it is larger than the sum of its proper divisors (20601634).

21378830 is a wasteful number, since it uses less digits than its factorization.

21378830 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 194371.

The product of its (nonzero) digits is 8064, while the sum is 32.

The square root of 21378830 is about 4623.7246890359. The cubic root of 21378830 is about 277.5415299152.

The spelling of 21378830 in words is "twenty-one million, three hundred seventy-eight thousand, eight hundred thirty".