21249678 has 8 divisors (see below), whose sum is σ = 42499368. Its totient is φ = 7083224.

The previous prime is 21249673. The next prime is 21249691. The reversal of 21249678 is 87694212.

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

21249678 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21249671) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1770801 + ... + 1770812.

It is an arithmetic number, because the mean of its divisors is an integer number (5312421).

Almost surely, 2^21249678 is an apocalyptic number.

21249678 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.

21249678 is a wasteful number, since it uses less digits than its factorization.

21249678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3541618.

The product of its digits is 48384, while the sum is 39.

The square root of 21249678 is about 4609.7373027104. The cubic root of 21249678 is about 276.9815137954.

The spelling of 21249678 in words is "twenty-one million, two hundred forty-nine thousand, six hundred seventy-eight".