21939634 has 4 divisors (see below), whose sum is σ = 32909454. Its totient is φ = 10969816.

The previous prime is 21939607. The next prime is 21939641. The reversal of 21939634 is 43693912.

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

It can be written as a sum of positive squares in only one way, i.e., 21576025 + 363609 = 4645^2 + 603^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21939593 and 21939602.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5484907 + ... + 5484910.

Almost surely, 2^21939634 is an apocalyptic number.

21939634 is a deficient number, since it is larger than the sum of its proper divisors (10969820).

21939634 is a wasteful number, since it uses less digits than its factorization.

21939634 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10969819.

The product of its digits is 34992, while the sum is 37.

The square root of 21939634 is about 4683.9763022458. The cubic root of 21939634 is about 279.9474135938.

The spelling of 21939634 in words is "twenty-one million, nine hundred thirty-nine thousand, six hundred thirty-four".