31323143440 has 40 divisors (see below), whose sum is σ = 73203682968. Its totient is φ = 12464332800.

The previous prime is 31323143431. The next prime is 31323143459. The reversal of 31323143440 is 4434132313.

It can be written as a sum of positive squares in 4 ways, for example, as 63489024 + 31259654416 = 7968^2 + 176804^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×31323143440² (a number of 22 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 31323143399 and 31323143408.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 998911 + ... + 1029790.

Almost surely, 2^31323143440 is an apocalyptic number.

It is an amenable number.

31323143440 is an abundant number, since it is smaller than the sum of its proper divisors (41880539528).

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

31323143440 is a wasteful number, since it uses less digits than its factorization.

31323143440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2028907 (or 2028901 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 28.

Adding to 31323143440 its reverse (4434132313), we get a palindrome (35757275753).

The spelling of 31323143440 in words is "thirty-one billion, three hundred twenty-three million, one hundred forty-three thousand, four hundred forty".