1264002640 has 40 divisors (see below), whose sum is σ = 2955076488. Its totient is φ = 502801920.

The previous prime is 1264002589. The next prime is 1264002647. The reversal of 1264002640 is 462004621.

It can be written as a sum of positive squares in 4 ways, for example, as 74580496 + 1189422144 = 8636^2 + 34488^2 .

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

It is a super-3 number, since 3×1264002640³ (a number of 28 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1264002647) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29167 + ... + 58126.

Almost surely, 2^1264002640 is an apocalyptic number.

1264002640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1264002640 is an abundant number, since it is smaller than the sum of its proper divisors (1691073848).

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

1264002640 is a wasteful number, since it uses less digits than its factorization.

1264002640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87487 (or 87481 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 1264002640 is about 35552.8147971437. The cubic root of 1264002640 is about 1081.2247879004.

The spelling of 1264002640 in words is "one billion, two hundred sixty-four million, two thousand, six hundred forty".