31281553440 has 72 divisors (see below), whose sum is σ = 106748306028. Its totient is φ = 8341747200.

The previous prime is 31281553427. The next prime is 31281553483. The reversal of 31281553440 is 4435518213.

31281553440 is a `hidden beast` number, since 3 + 1 + 2 + 81 + 5 + 534 + 40 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 28454291856 + 2827261584 = 168684^2 + 53172^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 31281553395 and 31281553404.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10860211 + ... + 10863090.

Almost surely, 2^31281553440 is an apocalyptic number.

31281553440 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31281553440 is an abundant number, since it is smaller than the sum of its proper divisors (75466752588).

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

31281553440 is a wasteful number, since it uses less digits than its factorization.

31281553440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21723322 (or 21723311 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The spelling of 31281553440 in words is "thirty-one billion, two hundred eighty-one million, five hundred fifty-three thousand, four hundred forty".