21354831 has 6 divisors (see below), whose sum is σ = 30845880. Its totient is φ = 14236548.

The previous prime is 21354799. The next prime is 21354847. The reversal of 21354831 is 13845312.

It is a happy number.

It is not a de Polignac number, because 21354831 - 2⁵ = 21354799 is a prime.

It is a super-2 number, since 2×21354831² = 912057614077122, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21354795 and 21354804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21314831) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1186371 + ... + 1186388.

It is an arithmetic number, because the mean of its divisors is an integer number (5140980).

Almost surely, 2^21354831 is an apocalyptic number.

21354831 is a deficient number, since it is larger than the sum of its proper divisors (9491049).

21354831 is a wasteful number, since it uses less digits than its factorization.

21354831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2372765 (or 2372762 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 21354831 is about 4621.1287582148. The cubic root of 21354831 is about 277.4376387748.

The spelling of 21354831 in words is "twenty-one million, three hundred fifty-four thousand, eight hundred thirty-one".