21948797 has 4 divisors (see below), whose sum is σ = 23637180. Its totient is φ = 20260416.

The previous prime is 21948793. The next prime is 21948799. The reversal of 21948797 is 79784912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1976836 + 19971961 = 1406^2 + 4469^2 .

It is a cyclic number.

It is not a de Polignac number, because 21948797 - 2² = 21948793 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 (21948793) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 844172 + ... + 844197.

It is an arithmetic number, because the mean of its divisors is an integer number (5909295).

Almost surely, 2^21948797 is an apocalyptic number.

It is an amenable number.

21948797 is a deficient number, since it is larger than the sum of its proper divisors (1688383).

21948797 is a wasteful number, since it uses less digits than its factorization.

21948797 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1688382.

The product of its digits is 254016, while the sum is 47.

The square root of 21948797 is about 4684.9543220826. The cubic root of 21948797 is about 279.9863811403.

The spelling of 21948797 in words is "twenty-one million, nine hundred forty-eight thousand, seven hundred ninety-seven".