21902378 has 4 divisors (see below), whose sum is σ = 32853570. Its totient is φ = 10951188.

The previous prime is 21902347. The next prime is 21902407. The reversal of 21902378 is 87320912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 15737089 + 6165289 = 3967^2 + 2483^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5475593 + ... + 5475596.

Almost surely, 2^21902378 is an apocalyptic number.

21902378 is a deficient number, since it is larger than the sum of its proper divisors (10951192).

21902378 is a wasteful number, since it uses less digits than its factorization.

21902378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10951191.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 21902378 is about 4679.9976495721. The cubic root of 21902378 is about 279.7888629387.

The spelling of 21902378 in words is "twenty-one million, nine hundred two thousand, three hundred seventy-eight".