21729496 has 8 divisors (see below), whose sum is σ = 40742820. Its totient is φ = 10864744.

The previous prime is 21729473. The next prime is 21729509. The reversal of 21729496 is 69492712.

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-3 number, since 3×21729496³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 1358086 + ... + 1358101.

Almost surely, 2^21729496 is an apocalyptic number.

It is an amenable number.

21729496 is a deficient number, since it is larger than the sum of its proper divisors (19013324).

21729496 is a wasteful number, since it uses less digits than its factorization.

21729496 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2716193 (or 2716189 counting only the distinct ones).

The product of its digits is 54432, while the sum is 40.

The square root of 21729496 is about 4661.4907486769. The cubic root of 21729496 is about 279.0507652044.

The spelling of 21729496 in words is "twenty-one million, seven hundred twenty-nine thousand, four hundred ninety-six".