20981597 has 8 divisors (see below), whose sum is σ = 25823616. Its totient is φ = 16600752.

The previous prime is 20981593. The next prime is 20981617. The reversal of 20981597 is 79518902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20981597 - 2² = 20981593 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20981593) 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 7 ways as a sum of consecutive naturals, for example, 115193 + ... + 115374.

It is an arithmetic number, because the mean of its divisors is an integer number (3227952).

Almost surely, 2^20981597 is an apocalyptic number.

It is an amenable number.

20981597 is a deficient number, since it is larger than the sum of its proper divisors (4842019).

20981597 is a wasteful number, since it uses less digits than its factorization.

20981597 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230587.

The product of its (nonzero) digits is 45360, while the sum is 41.

The square root of 20981597 is about 4580.5673229416. The cubic root of 20981597 is about 275.8118028444.

The spelling of 20981597 in words is "twenty million, nine hundred eighty-one thousand, five hundred ninety-seven".