21603607 has 2 divisors, whose sum is σ = 21603608. Its totient is φ = 21603606.

The previous prime is 21603599. The next prime is 21603613. The reversal of 21603607 is 70630612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21603607 - 2³ = 21603599 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21603007) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10801803 + 10801804.

It is an arithmetic number, because the mean of its divisors is an integer number (10801804).

Almost surely, 2^21603607 is an apocalyptic number.

21603607 is a deficient number, since it is larger than the sum of its proper divisors (1).

21603607 is an equidigital number, since it uses as much as digits as its factorization.

21603607 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1512, while the sum is 25.

The square root of 21603607 is about 4647.9680506647. The cubic root of 21603607 is about 278.5108312011.

The spelling of 21603607 in words is "twenty-one million, six hundred three thousand, six hundred seven".