21739297 has 8 divisors (see below), whose sum is σ = 22117536. Its totient is φ = 21364512.

The previous prime is 21739261. The next prime is 21739303. The reversal of 21739297 is 79293712.

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 21739297 - 2¹¹ = 21737249 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21739247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13918 + ... + 15400.

It is an arithmetic number, because the mean of its divisors is an integer number (2764692).

Almost surely, 2^21739297 is an apocalyptic number.

It is an amenable number.

21739297 is a deficient number, since it is larger than the sum of its proper divisors (378239).

21739297 is a wasteful number, since it uses less digits than its factorization.

21739297 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1727.

The product of its digits is 47628, while the sum is 40.

The square root of 21739297 is about 4662.5419032970. The cubic root of 21739297 is about 279.0927137990.

The spelling of 21739297 in words is "twenty-one million, seven hundred thirty-nine thousand, two hundred ninety-seven".