21492347 has 4 divisors (see below), whose sum is σ = 21501960. Its totient is φ = 21482736.

The previous prime is 21492259. The next prime is 21492349. The reversal of 21492347 is 74329412.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21492347 - 2¹⁸ = 21230203 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21492349) 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, 503 + ... + 6575.

It is an arithmetic number, because the mean of its divisors is an integer number (5375490).

Almost surely, 2^21492347 is an apocalyptic number.

21492347 is a deficient number, since it is larger than the sum of its proper divisors (9613).

21492347 is an equidigital number, since it uses as much as digits as its factorization.

21492347 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9612.

The product of its digits is 12096, while the sum is 32.

The square root of 21492347 is about 4635.9839300843. The cubic root of 21492347 is about 278.0318916883.

The spelling of 21492347 in words is "twenty-one million, four hundred ninety-two thousand, three hundred forty-seven".