21951797 has 8 divisors (see below), whose sum is σ = 25234176. Its totient is φ = 18706032.

The previous prime is 21951793. The next prime is 21951803. The reversal of 21951797 is 79715912.

It is a happy number.

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 21951797 - 2² = 21951793 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21951793) 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, 7853 + ... + 10274.

It is an arithmetic number, because the mean of its divisors is an integer number (3154272).

Almost surely, 2^21951797 is an apocalyptic number.

It is an amenable number.

21951797 is a deficient number, since it is larger than the sum of its proper divisors (3282379).

21951797 is a wasteful number, since it uses less digits than its factorization.

21951797 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18307.

The product of its digits is 39690, while the sum is 41.

The square root of 21951797 is about 4685.2744850222. The cubic root of 21951797 is about 279.9991369021. Note that the first 3 decimals are identical.

The spelling of 21951797 in words is "twenty-one million, nine hundred fifty-one thousand, seven hundred ninety-seven".