21399434 has 16 divisors (see below), whose sum is σ = 38616000. Its totient is φ = 8688384.

The previous prime is 21399421. The next prime is 21399437. The reversal of 21399434 is 43499312.

It is a junction number, because it is equal to n+sod(n) for n = 21399394 and 21399403.

It is not an unprimeable number, because it can be changed into a prime (21399437) 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, 39959 + ... + 40490.

It is an arithmetic number, because the mean of its divisors is an integer number (2413500).

Almost surely, 2^21399434 is an apocalyptic number.

21399434 is a deficient number, since it is larger than the sum of its proper divisors (17216566).

21399434 is a wasteful number, since it uses less digits than its factorization.

21399434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80477.

The product of its digits is 23328, while the sum is 35.

The square root of 21399434 is about 4625.9522262989. The cubic root of 21399434 is about 277.6306621641.

The spelling of 21399434 in words is "twenty-one million, three hundred ninety-nine thousand, four hundred thirty-four".