21347409 has 8 divisors (see below), whose sum is σ = 29232640. Its totient is φ = 13846896.

The previous prime is 21347371. The next prime is 21347419. The reversal of 21347409 is 90474312.

It is a happy number.

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

It is a de Polignac number, because none of the positive numbers 2^k-21347409 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21347419) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 96049 + ... + 96270.

It is an arithmetic number, because the mean of its divisors is an integer number (3654080).

Almost surely, 2^21347409 is an apocalyptic number.

It is an amenable number.

21347409 is a deficient number, since it is larger than the sum of its proper divisors (7885231).

21347409 is a wasteful number, since it uses less digits than its factorization.

21347409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192359.

The product of its (nonzero) digits is 6048, while the sum is 30.

The square root of 21347409 is about 4620.3256378745. The cubic root of 21347409 is about 277.4054933436.

The spelling of 21347409 in words is "twenty-one million, three hundred forty-seven thousand, four hundred nine".