642723428081 has 16 divisors (see below), whose sum is σ = 751684454400. Its totient is φ = 538050331728.

The previous prime is 642723428047. The next prime is 642723428117. The reversal of 642723428081 is 180824327246.

It is not a de Polignac number, because 642723428081 - 2¹⁴ = 642723411697 is a prime.

It is a super-2 number, since 2×642723428081² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642723428681) 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, 3935000 + ... + 4095078.

It is an arithmetic number, because the mean of its divisors is an integer number (46980278400).

Almost surely, 2^642723428081 is an apocalyptic number.

It is an amenable number.

642723428081 is a deficient number, since it is larger than the sum of its proper divisors (108961026319).

642723428081 is a wasteful number, since it uses less digits than its factorization.

642723428081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173468.

The product of its (nonzero) digits is 1032192, while the sum is 47.

The spelling of 642723428081 in words is "six hundred forty-two billion, seven hundred twenty-three million, four hundred twenty-eight thousand, eighty-one".