21209934 has 8 divisors (see below), whose sum is σ = 42419880. Its totient is φ = 7069976.

The previous prime is 21209927. The next prime is 21209957. The reversal of 21209934 is 43990212.

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

21209934 is an admirable number.

It is a super-2 number, since 2×21209934² = 899722600568712, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1767489 + ... + 1767500.

It is an arithmetic number, because the mean of its divisors is an integer number (5302485).

Almost surely, 2^21209934 is an apocalyptic number.

21209934 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21209934 is a wasteful number, since it uses less digits than its factorization.

21209934 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3534994.

The product of its (nonzero) digits is 3888, while the sum is 30.

The square root of 21209934 is about 4605.4244104100. The cubic root of 21209934 is about 276.8087233571.

The spelling of 21209934 in words is "twenty-one million, two hundred nine thousand, nine hundred thirty-four".