642738756 has 48 divisors (see below), whose sum is σ = 1637572608. Its totient is φ = 194589600.

The previous prime is 642738751. The next prime is 642738773. The reversal of 642738756 is 657837246.

It is a super-2 number, since 2×642738756² = 826226216928855072, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (642738751) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 239301 + ... + 241971.

It is an arithmetic number, because the mean of its divisors is an integer number (34116096).

Almost surely, 2^642738756 is an apocalyptic number.

642738756 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

642738756 is an abundant number, since it is smaller than the sum of its proper divisors (994833852).

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

642738756 is a wasteful number, since it uses less digits than its factorization.

642738756 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4512 (or 4510 counting only the distinct ones).

The product of its digits is 1693440, while the sum is 48.

The square root of 642738756 is about 25352.2929140541. The cubic root of 642738756 is about 863.0013914807.

The spelling of 642738756 in words is "six hundred forty-two million, seven hundred thirty-eight thousand, seven hundred fifty-six".