21395351 has 4 divisors (see below), whose sum is σ = 21688512. Its totient is φ = 21102192.

The previous prime is 21395329. The next prime is 21395383. The reversal of 21395351 is 15359312.

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 21395351 - 2¹⁰ = 21394327 is a prime.

It is a super-2 number, since 2×21395351² = 915522088826402, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21395321) 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, 146471 + ... + 146616.

It is an arithmetic number, because the mean of its divisors is an integer number (5422128).

Almost surely, 2^21395351 is an apocalyptic number.

21395351 is a deficient number, since it is larger than the sum of its proper divisors (293161).

21395351 is an equidigital number, since it uses as much as digits as its factorization.

21395351 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 293160.

The product of its digits is 4050, while the sum is 29.

The square root of 21395351 is about 4625.5108907017. The cubic root of 21395351 is about 277.6130037828.

The spelling of 21395351 in words is "twenty-one million, three hundred ninety-five thousand, three hundred fifty-one".