21497983 has 6 divisors (see below), whose sum is σ = 23279064. Its totient is φ = 19844136.

The previous prime is 21497977. The next prime is 21498041. The reversal of 21497983 is 38979412.

It is not a de Polignac number, because 21497983 - 2¹³ = 21489791 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 (21497933) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 63435 + ... + 63772.

It is an arithmetic number, because the mean of its divisors is an integer number (3879844).

Almost surely, 2^21497983 is an apocalyptic number.

21497983 is a deficient number, since it is larger than the sum of its proper divisors (1781081).

21497983 is a wasteful number, since it uses less digits than its factorization.

21497983 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127233 (or 127220 counting only the distinct ones).

The product of its digits is 108864, while the sum is 43.

The square root of 21497983 is about 4636.5917439430. The cubic root of 21497983 is about 278.0561925986.

The spelling of 21497983 in words is "twenty-one million, four hundred ninety-seven thousand, nine hundred eighty-three".