21849878 has 4 divisors (see below), whose sum is σ = 32774820. Its totient is φ = 10924938.

The previous prime is 21849857. The next prime is 21849881. The reversal of 21849878 is 87894812.

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

It is a super-2 number, since 2×21849878² = 954834337229768, which contains 22 as substring.

It is a congruent 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 as a sum of consecutive naturals, namely, 5462468 + ... + 5462471.

It is an arithmetic number, because the mean of its divisors is an integer number (8193705).

Almost surely, 2^21849878 is an apocalyptic number.

21849878 is a deficient number, since it is larger than the sum of its proper divisors (10924942).

21849878 is a wasteful number, since it uses less digits than its factorization.

21849878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10924941.

The product of its digits is 258048, while the sum is 47.

The square root of 21849878 is about 4674.3853071821. The cubic root of 21849878 is about 279.5651327817.

The spelling of 21849878 in words is "twenty-one million, eight hundred forty-nine thousand, eight hundred seventy-eight".