21351197 has 8 divisors (see below), whose sum is σ = 24437952. Its totient is φ = 18273600.

The previous prime is 21351181. The next prime is 21351217. The reversal of 21351197 is 79115312.

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 21351197 - 2⁴ = 21351181 is a prime.

It is a super-2 number, since 2×21351197² = 911747226665618, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21353197) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3797 + ... + 7557.

It is an arithmetic number, because the mean of its divisors is an integer number (3054744).

Almost surely, 2^21351197 is an apocalyptic number.

It is an amenable number.

21351197 is a deficient number, since it is larger than the sum of its proper divisors (3086755).

21351197 is an equidigital number, since it uses as much as digits as its factorization.

21351197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4579.

The product of its digits is 1890, while the sum is 29.

The square root of 21351197 is about 4620.7355475076. The cubic root of 21351197 is about 277.4219004848.

The spelling of 21351197 in words is "twenty-one million, three hundred fifty-one thousand, one hundred ninety-seven".