20981693 has 8 divisors (see below), whose sum is σ = 21835008. Its totient is φ = 20145424.

The previous prime is 20981677. The next prime is 20981711. The reversal of 20981693 is 39618902.

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 20981693 - 2⁴ = 20981677 is a prime.

It is a super-2 number, since 2×20981693² = 880462882292498, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20981663) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1721 + ... + 6702.

It is an arithmetic number, because the mean of its divisors is an integer number (2729376).

Almost surely, 2^20981693 is an apocalyptic number.

It is an amenable number.

20981693 is a deficient number, since it is larger than the sum of its proper divisors (853315).

20981693 is an equidigital number, since it uses as much as digits as its factorization.

20981693 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8523.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 20981693 is about 4580.5778019809. The cubic root of 20981693 is about 275.8122234970.

The spelling of 20981693 in words is "twenty million, nine hundred eighty-one thousand, six hundred ninety-three".