21357203 has 4 divisors (see below), whose sum is σ = 24408240. Its totient is φ = 18306168.

The previous prime is 21357199. The next prime is 21357247. The reversal of 21357203 is 30275312.

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

It is a cyclic number.

It is not a de Polignac number, because 21357203 - 2² = 21357199 is a prime.

It is a super-2 number, since 2×21357203² = 912260239966418, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21357263) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1525508 + ... + 1525521.

It is an arithmetic number, because the mean of its divisors is an integer number (6102060).

Almost surely, 2^21357203 is an apocalyptic number.

21357203 is a deficient number, since it is larger than the sum of its proper divisors (3051037).

21357203 is an equidigital number, since it uses as much as digits as its factorization.

21357203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3051036.

The product of its (nonzero) digits is 1260, while the sum is 23.

The square root of 21357203 is about 4621.3853983411. The cubic root of 21357203 is about 277.4479105757.

The spelling of 21357203 in words is "twenty-one million, three hundred fifty-seven thousand, two hundred three".