20851532478 has 96 divisors (see below), whose sum is σ = 54805533120. Its totient is φ = 5593190400.

The previous prime is 20851532431. The next prime is 20851532491. The reversal of 20851532478 is 87423515802.

20851532478 is a `hidden beast` number, since 20 + 8 + 5 + 153 + 2 + 478 = 666.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 864178 + ... + 887978.

It is an arithmetic number, because the mean of its divisors is an integer number (570890970).

Almost surely, 2^20851532478 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20851532478, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27402766560).

20851532478 is an abundant number, since it is smaller than the sum of its proper divisors (33954000642).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20851532478 is a wasteful number, since it uses less digits than its factorization.

20851532478 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24242 (or 24239 counting only the distinct ones).

The product of its (nonzero) digits is 537600, while the sum is 45.

The spelling of 20851532478 in words is "twenty billion, eight hundred fifty-one million, five hundred thirty-two thousand, four hundred seventy-eight".