64642089081 has 4 divisors (see below), whose sum is σ = 86189452112. Its totient is φ = 43094726052.

The previous prime is 64642089077. The next prime is 64642089103. The reversal of 64642089081 is 18098024646.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 64642089081 - 2² = 64642089077 is a prime.

It is a super-2 number, since 2×64642089081² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 64642089081.

It is not an unprimeable number, because it can be changed into a prime (64642089041) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10773681511 + ... + 10773681516.

It is an arithmetic number, because the mean of its divisors is an integer number (21547363028).

Almost surely, 2^64642089081 is an apocalyptic number.

It is an amenable number.

64642089081 is a deficient number, since it is larger than the sum of its proper divisors (21547363031).

64642089081 is a wasteful number, since it uses less digits than its factorization.

64642089081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21547363030.

The product of its (nonzero) digits is 663552, while the sum is 48.

The spelling of 64642089081 in words is "sixty-four billion, six hundred forty-two million, eighty-nine thousand, eighty-one".