20001261 has 24 divisors (see below), whose sum is σ = 31347264. Its totient is φ = 11309760.

The previous prime is 20001259. The next prime is 20001263. The reversal of 20001261 is 16210002.

It is an interprime number because it is at equal distance from previous prime (20001259) and next prime (20001263).

It is not a de Polignac number, because 20001261 - 2¹ = 20001259 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20001263) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 14481 + ... + 15801.

It is an arithmetic number, because the mean of its divisors is an integer number (1306136).

Almost surely, 2^20001261 is an apocalyptic number.

20001261 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20001261 is a deficient number, since it is larger than the sum of its proper divisors (11346003).

20001261 is a wasteful number, since it uses less digits than its factorization.

20001261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1441 (or 1434 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 20001261 is about 4472.2769368634. The cubic root of 20001261 is about 271.4474663406.

Adding to 20001261 its reverse (16210002), we get a palindrome (36211263).

The spelling of 20001261 in words is "twenty million, one thousand, two hundred sixty-one".