21731416 has 32 divisors (see below), whose sum is σ = 46766880. Its totient is φ = 9273600.

The previous prime is 21731377. The next prime is 21731417. The reversal of 21731416 is 61413712.

21731416 = 126² + 127² + ... + 406².

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21731417) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15046 + ... + 16426.

It is an arithmetic number, because the mean of its divisors is an integer number (1461465).

Almost surely, 2^21731416 is an apocalyptic number.

It is an amenable number.

21731416 is an abundant number, since it is smaller than the sum of its proper divisors (25035464).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21731416 is a wasteful number, since it uses less digits than its factorization.

21731416 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1675 (or 1671 counting only the distinct ones).

The product of its digits is 1008, while the sum is 25.

The square root of 21731416 is about 4661.6966868298. The cubic root of 21731416 is about 279.0589838594.

The spelling of 21731416 in words is "twenty-one million, seven hundred thirty-one thousand, four hundred sixteen".