21539038 has 4 divisors (see below), whose sum is σ = 32308560. Its totient is φ = 10769518.

The previous prime is 21539033. The next prime is 21539047. The reversal of 21539038 is 83093512.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21539033) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5384758 + ... + 5384761.

It is an arithmetic number, because the mean of its divisors is an integer number (8077140).

Almost surely, 2^21539038 is an apocalyptic number.

21539038 is a deficient number, since it is larger than the sum of its proper divisors (10769522).

21539038 is a wasteful number, since it uses less digits than its factorization.

21539038 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10769521.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 21539038 is about 4641.0169144273. The cubic root of 21539038 is about 278.2330826483.

The spelling of 21539038 in words is "twenty-one million, five hundred thirty-nine thousand, thirty-eight".