21486831 has 8 divisors (see below), whose sum is σ = 28722864. Its totient is φ = 14287680.

The previous prime is 21486821. The next prime is 21486859. The reversal of 21486831 is 13868412.

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

It is not a de Polignac number, because 21486831 - 2²³ = 13098223 is a prime.

It is a super-2 number, since 2×21486831² = 923367812845122, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21486792 and 21486801.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21486811) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 7830 + ... + 10211.

It is an arithmetic number, because the mean of its divisors is an integer number (3590358).

Almost surely, 2^21486831 is an apocalyptic number.

21486831 is a deficient number, since it is larger than the sum of its proper divisors (7236033).

21486831 is a wasteful number, since it uses less digits than its factorization.

21486831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18441.

The product of its digits is 9216, while the sum is 33.

The square root of 21486831 is about 4635.3889804417. The cubic root of 21486831 is about 278.0081040717.

The spelling of 21486831 in words is "twenty-one million, four hundred eighty-six thousand, eight hundred thirty-one".