21247886 has 32 divisors (see below), whose sum is σ = 35997696. Its totient is φ = 9324000.

The previous prime is 21247873. The next prime is 21247913. The reversal of 21247886 is 68874212.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 95171 + ... + 95393.

It is an arithmetic number, because the mean of its divisors is an integer number (1124928).

Almost surely, 2^21247886 is an apocalyptic number.

21247886 is a deficient number, since it is larger than the sum of its proper divisors (14749810).

21247886 is a wasteful number, since it uses less digits than its factorization.

21247886 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 368.

The product of its digits is 43008, while the sum is 38.

The square root of 21247886 is about 4609.5429274495. The cubic root of 21247886 is about 276.9737275625.

The spelling of 21247886 in words is "twenty-one million, two hundred forty-seven thousand, eight hundred eighty-six".