21375603 has 16 divisors (see below), whose sum is σ = 32524960. Its totient is φ = 13864608.

The previous prime is 21375587. The next prime is 21375611. The reversal of 21375603 is 30657312.

It is a happy number.

21375603 is a `hidden beast` number, since 21 + 37 + 5 + 603 = 666.

It is not a de Polignac number, because 21375603 - 2⁴ = 21375587 is a prime.

It is a super-2 number, since 2×21375603² = 913832807227218, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21375503) 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, 9700 + ... + 11697.

It is an arithmetic number, because the mean of its divisors is an integer number (2032810).

Almost surely, 2^21375603 is an apocalyptic number.

21375603 is a deficient number, since it is larger than the sum of its proper divisors (11149357).

21375603 is a wasteful number, since it uses less digits than its factorization.

21375603 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21443 (or 21437 counting only the distinct ones).

The product of its (nonzero) digits is 3780, while the sum is 27.

The square root of 21375603 is about 4623.3757147781. The cubic root of 21375603 is about 277.5275648294.

The spelling of 21375603 in words is "twenty-one million, three hundred seventy-five thousand, six hundred three".