21371397 has 8 divisors (see below), whose sum is σ = 30171456. Its totient is φ = 13409472.

The previous prime is 21371377. The next prime is 21371401. The reversal of 21371397 is 79317312.

It is a happy number.

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

It is not a de Polignac number, because 21371397 - 2⁷ = 21371269 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21371377) 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, 209473 + ... + 209574.

It is an arithmetic number, because the mean of its divisors is an integer number (3771432).

Almost surely, 2^21371397 is an apocalyptic number.

It is an amenable number.

21371397 is a deficient number, since it is larger than the sum of its proper divisors (8800059).

21371397 is a wasteful number, since it uses less digits than its factorization.

21371397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 419067.

The product of its digits is 7938, while the sum is 33.

The square root of 21371397 is about 4622.9208299516. The cubic root of 21371397 is about 277.5093609374.

The spelling of 21371397 in words is "twenty-one million, three hundred seventy-one thousand, three hundred ninety-seven".