21739603 has 2 divisors, whose sum is σ = 21739604. Its totient is φ = 21739602.

The previous prime is 21739537. The next prime is 21739637. The reversal of 21739603 is 30693712.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21739603 is a prime.

It is a super-2 number, since 2×21739603² = 945220677195218, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21739643) by changing a digit.

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, 10869801 + 10869802.

It is an arithmetic number, because the mean of its divisors is an integer number (10869802).

Almost surely, 2^21739603 is an apocalyptic number.

21739603 is a deficient number, since it is larger than the sum of its proper divisors (1).

21739603 is an equidigital number, since it uses as much as digits as its factorization.

21739603 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6804, while the sum is 31.

The square root of 21739603 is about 4662.5747179000. The cubic root of 21739603 is about 279.0940232858.

The spelling of 21739603 in words is "twenty-one million, seven hundred thirty-nine thousand, six hundred three".