21212697 has 8 divisors (see below), whose sum is σ = 30854880. Its totient is φ = 12856160.

The previous prime is 21212677. The next prime is 21212701. The reversal of 21212697 is 79621212.

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 21212697 - 2¹¹ = 21210649 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21212627) 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, 321372 + ... + 321437.

It is an arithmetic number, because the mean of its divisors is an integer number (3856860).

Almost surely, 2^21212697 is an apocalyptic number.

It is an amenable number.

21212697 is a deficient number, since it is larger than the sum of its proper divisors (9642183).

21212697 is a wasteful number, since it uses less digits than its factorization.

21212697 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 642823.

The product of its digits is 3024, while the sum is 30.

The square root of 21212697 is about 4605.7243729950. The cubic root of 21212697 is about 276.8207427139.

The spelling of 21212697 in words is "twenty-one million, two hundred twelve thousand, six hundred ninety-seven".