51449599920 has 320 divisors, whose sum is σ = 171669012480. Its totient is φ = 12708347904.

The previous prime is 51449599891. The next prime is 51449600077. The reversal of 51449599920 is 2999594415.

It is a super-2 number, since 2×51449599920² (a number of 22 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 42275152 + ... + 42276368.

It is an arithmetic number, because the mean of its divisors is an integer number (536465664).

Almost surely, 2^51449599920 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51449599920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (85834506240).

51449599920 is an abundant number, since it is smaller than the sum of its proper divisors (120219412560).

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

51449599920 is a wasteful number, since it uses less digits than its factorization.

51449599920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1452 (or 1446 counting only the distinct ones).

The product of its (nonzero) digits is 5248800, while the sum is 57.

The spelling of 51449599920 in words is "fifty-one billion, four hundred forty-nine million, five hundred ninety-nine thousand, nine hundred twenty".