21376778 has 8 divisors (see below), whose sum is σ = 32085120. Its totient is φ = 10681740.

The previous prime is 21376759. The next prime is 21376783. The reversal of 21376778 is 87767312.

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

It is a super-2 number, since 2×21376778² = 913933275322568, which contains 22 as substring.

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 in 3 ways as a sum of consecutive naturals, for example, 3473 + ... + 7403.

It is an arithmetic number, because the mean of its divisors is an integer number (4010640).

Almost surely, 2^21376778 is an apocalyptic number.

21376778 is a deficient number, since it is larger than the sum of its proper divisors (10708342).

21376778 is a wasteful number, since it uses less digits than its factorization.

21376778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6652.

The product of its digits is 98784, while the sum is 41.

The square root of 21376778 is about 4623.5027846861. The cubic root of 21376778 is about 277.5326498932.

The spelling of 21376778 in words is "twenty-one million, three hundred seventy-six thousand, seven hundred seventy-eight".