20981509474 has 8 divisors (see below), whose sum is σ = 31903391340. Its totient is φ = 10347045696.

The previous prime is 20981509441. The next prime is 20981509477. The reversal of 20981509474 is 47490518902.

It can be written as a sum of positive squares in 2 ways, for example, as 20892678849 + 88830625 = 144543^2 + 9425^2 .

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

It is not an unprimeable number, because it can be changed into a prime (20981509477) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 71854339 + ... + 71854630.

Almost surely, 2^20981509474 is an apocalyptic number.

20981509474 is a deficient number, since it is larger than the sum of its proper divisors (10921881866).

20981509474 is a wasteful number, since it uses less digits than its factorization.

20981509474 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143709044.

The product of its (nonzero) digits is 725760, while the sum is 49.

The spelling of 20981509474 in words is "twenty billion, nine hundred eighty-one million, five hundred nine thousand, four hundred seventy-four".