21030253 has 8 divisors (see below), whose sum is σ = 21603456. Its totient is φ = 20460000.

The previous prime is 21030239. The next prime is 21030287. The reversal of 21030253 is 35203012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21030253 - 2⁹ = 21029741 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21030203) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27628 + ... + 28378.

It is an arithmetic number, because the mean of its divisors is an integer number (2700432).

Almost surely, 2^21030253 is an apocalyptic number.

It is an amenable number.

21030253 is a deficient number, since it is larger than the sum of its proper divisors (573203).

21030253 is an equidigital number, since it uses as much as digits as its factorization.

21030253 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1475.

The product of its (nonzero) digits is 180, while the sum is 16.

The square root of 21030253 is about 4585.8753799029. The cubic root of 21030253 is about 276.0248393594.

Adding to 21030253 its reverse (35203012), we get a palindrome (56233265).

The spelling of 21030253 in words is "twenty-one million, thirty thousand, two hundred fifty-three".