20725981 has 8 divisors (see below), whose sum is σ = 21762720. Its totient is φ = 19710768.

The previous prime is 20725961. The next prime is 20725993. The reversal of 20725981 is 18952702.

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 20725981 - 2⁷ = 20725853 is a prime.

It is a super-2 number, since 2×20725981² = 859132576824722, 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 (20725931) 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, 3391 + ... + 7276.

It is an arithmetic number, because the mean of its divisors is an integer number (2720340).

Almost surely, 2^20725981 is an apocalyptic number.

It is an amenable number.

20725981 is a deficient number, since it is larger than the sum of its proper divisors (1036739).

20725981 is a wasteful number, since it uses less digits than its factorization.

20725981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10763.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 20725981 is about 4552.5795984255. The cubic root of 20725981 is about 274.6871638161.

The spelling of 20725981 in words is "twenty million, seven hundred twenty-five thousand, nine hundred eighty-one".