21354378 has 8 divisors (see below), whose sum is σ = 42708768. Its totient is φ = 7118124.

The previous prime is 21354349. The next prime is 21354391. The reversal of 21354378 is 87345312.

It is a sphenic number, since it is the product of 3 distinct primes.

21354378 is an admirable number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 1779526 + ... + 1779537.

It is an arithmetic number, because the mean of its divisors is an integer number (5338596).

Almost surely, 2^21354378 is an apocalyptic number.

21354378 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21354378 is a wasteful number, since it uses less digits than its factorization.

21354378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3559068.

The product of its digits is 20160, while the sum is 33.

The square root of 21354378 is about 4621.0797439560. The cubic root of 21354378 is about 277.4356769996.

The spelling of 21354378 in words is "twenty-one million, three hundred fifty-four thousand, three hundred seventy-eight".