20905725 has 12 divisors (see below), whose sum is σ = 34564256. Its totient is φ = 11149680.

The previous prime is 20905711. The next prime is 20905727. The reversal of 20905725 is 52750902.

It is a happy number.

It is not a de Polignac number, because 20905725 - 2¹⁰ = 20904701 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20905692 and 20905701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20905727) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 139297 + ... + 139446.

Almost surely, 2^20905725 is an apocalyptic number.

20905725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20905725 is a deficient number, since it is larger than the sum of its proper divisors (13658531).

20905725 is a wasteful number, since it uses less digits than its factorization.

20905725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 278756 (or 278751 counting only the distinct ones).

The product of its (nonzero) digits is 6300, while the sum is 30.

The square root of 20905725 is about 4572.2778786946. The cubic root of 20905725 is about 275.4789449908.

The spelling of 20905725 in words is "twenty million, nine hundred five thousand, seven hundred twenty-five".