21359399 has 8 divisors (see below), whose sum is σ = 22427760. Its totient is φ = 20313216.

The previous prime is 21359389. The next prime is 21359413. The reversal of 21359399 is 99395312.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21359399 - 2⁴ = 21359383 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21359329) 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, 3554 + ... + 7439.

It is an arithmetic number, because the mean of its divisors is an integer number (2803470).

Almost surely, 2^21359399 is an apocalyptic number.

21359399 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

21359399 is a deficient number, since it is larger than the sum of its proper divisors (1068361).

21359399 is a wasteful number, since it uses less digits than its factorization.

21359399 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11089.

The product of its digits is 65610, while the sum is 41.

The square root of 21359399 is about 4621.6229833252. The cubic root of 21359399 is about 277.4574195414.

The spelling of 21359399 in words is "twenty-one million, three hundred fifty-nine thousand, three hundred ninety-nine".