21581036858 has 8 divisors (see below), whose sum is σ = 32372401152. Its totient is φ = 10790236476.

The previous prime is 21581036843. The next prime is 21581036861. The reversal of 21581036858 is 85863018512.

It is a happy number.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26810 + ... + 209477.

It is an arithmetic number, because the mean of its divisors is an integer number (4046550144).

Almost surely, 2^21581036858 is an apocalyptic number.

21581036858 is a deficient number, since it is larger than the sum of its proper divisors (10791364294).

21581036858 is a wasteful number, since it uses less digits than its factorization.

21581036858 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 281956.

The product of its (nonzero) digits is 460800, while the sum is 47.

The spelling of 21581036858 in words is "twenty-one billion, five hundred eighty-one million, thirty-six thousand, eight hundred fifty-eight".