20719985 has 16 divisors (see below), whose sum is σ = 29211840. Its totient is φ = 13909440.

The previous prime is 20719981. The next prime is 20720027. The reversal of 20719985 is 58991702.

It is not a de Polignac number, because 20719985 - 2² = 20719981 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20719981) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13775 + ... + 15204.

It is an arithmetic number, because the mean of its divisors is an integer number (1825740).

Almost surely, 2^20719985 is an apocalyptic number.

It is an amenable number.

20719985 is a deficient number, since it is larger than the sum of its proper divisors (8491855).

20719985 is a wasteful number, since it uses less digits than its factorization.

20719985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29008.

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

The square root of 20719985 is about 4551.9210230407. The cubic root of 20719985 is about 274.6606723786.

The spelling of 20719985 in words is "twenty million, seven hundred nineteen thousand, nine hundred eighty-five".