20312805981 has 8 divisors (see below), whose sum is σ = 29167106080. Its totient is φ = 12500188272.

The previous prime is 20312805979. The next prime is 20312805983. The reversal of 20312805981 is 18950821302.

It is an interprime number because it is at equal distance from previous prime (20312805979) and next prime (20312805983).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20312805981 - 2¹ = 20312805979 is a prime.

It is a super-2 number, since 2×20312805981² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39), and also a Moran number because the ratio is a prime number: 520841179 = 20312805981 / (2 + 0 + 3 + 1 + 2 + 8 + 0 + 5 + 9 + 8 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20312805983) 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, 260420551 + ... + 260420628.

It is an arithmetic number, because the mean of its divisors is an integer number (3645888260).

Almost surely, 2^20312805981 is an apocalyptic number.

It is an amenable number.

20312805981 is a deficient number, since it is larger than the sum of its proper divisors (8854300099).

20312805981 is a wasteful number, since it uses less digits than its factorization.

20312805981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 520841195.

The product of its (nonzero) digits is 34560, while the sum is 39.

The spelling of 20312805981 in words is "twenty billion, three hundred twelve million, eight hundred five thousand, nine hundred eighty-one".