21969897 has 8 divisors (see below), whose sum is σ = 30085056. Its totient is φ = 14250672.

The previous prime is 21969887. The next prime is 21969911. The reversal of 21969897 is 79896912.

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 21969897 - 2⁴ = 21969881 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21969817) 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, 98853 + ... + 99074.

It is an arithmetic number, because the mean of its divisors is an integer number (3760632).

Almost surely, 2^21969897 is an apocalyptic number.

It is an amenable number.

21969897 is a deficient number, since it is larger than the sum of its proper divisors (8115159).

21969897 is a wasteful number, since it uses less digits than its factorization.

21969897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 197967.

The product of its digits is 489888, while the sum is 51.

The square root of 21969897 is about 4687.2056707595. The cubic root of 21969897 is about 280.0760720175.

The spelling of 21969897 in words is "twenty-one million, nine hundred sixty-nine thousand, eight hundred ninety-seven".