21399069 has 8 divisors (see below), whose sum is σ = 28553472. Its totient is φ = 14255360.

The previous prime is 21399047. The next prime is 21399097. The reversal of 21399069 is 96099312.

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 21399069 - 2⁷ = 21398941 is a prime.

It is a super-2 number, since 2×21399069² = 915840308133522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21399019) 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, 6397 + ... + 9149.

It is an arithmetic number, because the mean of its divisors is an integer number (3569184).

Almost surely, 2^21399069 is an apocalyptic number.

It is an amenable number.

21399069 is a deficient number, since it is larger than the sum of its proper divisors (7154403).

21399069 is a wasteful number, since it uses less digits than its factorization.

21399069 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5347.

The product of its (nonzero) digits is 26244, while the sum is 39.

The square root of 21399069 is about 4625.9127747937. The cubic root of 21399069 is about 277.6290836836.

The spelling of 21399069 in words is "twenty-one million, three hundred ninety-nine thousand, sixty-nine".