21739445 has 16 divisors (see below), whose sum is σ = 32108160. Its totient is φ = 13760064.

The previous prime is 21739441. The next prime is 21739451. The reversal of 21739445 is 54493712.

It is a cyclic number.

It is not a de Polignac number, because 21739445 - 2² = 21739441 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21739441) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 23435 + ... + 24344.

It is an arithmetic number, because the mean of its divisors is an integer number (2006760).

Almost surely, 2^21739445 is an apocalyptic number.

It is an amenable number.

21739445 is a deficient number, since it is larger than the sum of its proper divisors (10368715).

21739445 is a wasteful number, since it uses less digits than its factorization.

21739445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47804.

The product of its digits is 30240, while the sum is 35.

The square root of 21739445 is about 4662.5577744410. The cubic root of 21739445 is about 279.0933471471.

The spelling of 21739445 in words is "twenty-one million, seven hundred thirty-nine thousand, four hundred forty-five".