21619797 has 8 divisors (see below), whose sum is σ = 28877856. Its totient is φ = 14387472.

The previous prime is 21619789. The next prime is 21619811. The reversal of 21619797 is 79791612.

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 21619797 - 2³ = 21619789 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21614797) 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, 4378 + ... + 7899.

It is an arithmetic number, because the mean of its divisors is an integer number (3609732).

Almost surely, 2^21619797 is an apocalyptic number.

It is an amenable number.

21619797 is a deficient number, since it is larger than the sum of its proper divisors (7258059).

21619797 is a wasteful number, since it uses less digits than its factorization.

21619797 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12867.

The product of its digits is 47628, while the sum is 42.

The square root of 21619797 is about 4649.7093457549. The cubic root of 21619797 is about 278.5803869384.

The spelling of 21619797 in words is "twenty-one million, six hundred nineteen thousand, seven hundred ninety-seven".