21449731 has 4 divisors (see below), whose sum is σ = 22382352. Its totient is φ = 20517112.

The previous prime is 21449711. The next prime is 21449741. The reversal of 21449731 is 13794412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21449731 - 2¹¹ = 21447683 is a prime.

It is a super-2 number, since 2×21449731² = 920181919944722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21449693 and 21449702.

It is not an unprimeable number, because it can be changed into a prime (21449711) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 466276 + ... + 466321.

It is an arithmetic number, because the mean of its divisors is an integer number (5595588).

Almost surely, 2^21449731 is an apocalyptic number.

21449731 is a deficient number, since it is larger than the sum of its proper divisors (932621).

21449731 is an equidigital number, since it uses as much as digits as its factorization.

21449731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 932620.

The product of its digits is 6048, while the sum is 31.

The square root of 21449731 is about 4631.3854298687. The cubic root of 21449731 is about 277.8480053488.

The spelling of 21449731 in words is "twenty-one million, four hundred forty-nine thousand, seven hundred thirty-one".