1023156640 has 144 divisors (see below), whose sum is σ = 2723845320. Its totient is φ = 362700800.

The previous prime is 1023156559. The next prime is 1023156649. The reversal of 1023156640 is 466513201.

It can be written as a sum of positive squares in 4 ways, for example, as 718025616 + 305131024 = 26796^2 + 17468^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1023156599 and 1023156608.

It is not an unprimeable number, because it can be changed into a prime (1023156649) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 793116 + ... + 794404.

Almost surely, 2^1023156640 is an apocalyptic number.

1023156640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1023156640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1361922660).

1023156640 is an abundant number, since it is smaller than the sum of its proper divisors (1700688680).

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

1023156640 is a wasteful number, since it uses less digits than its factorization.

1023156640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1367 (or 1348 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 1023156640 is about 31986.8197856555. The cubic root of 1023156640 is about 1007.6600537550.

Adding to 1023156640 its reverse (466513201), we get a palindrome (1489669841).

The spelling of 1023156640 in words is "one billion, twenty-three million, one hundred fifty-six thousand, six hundred forty".