81228990001 has 4 divisors (see below), whose sum is σ = 82957266432. Its totient is φ = 79500713572.

The previous prime is 81228989987. The next prime is 81228990041. The reversal of 81228990001 is 10009982218.

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 a cyclic number.

It is not a de Polignac number, because 81228990001 - 2⁷ = 81228989873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81228990041) 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, 864138145 + ... + 864138238.

It is an arithmetic number, because the mean of its divisors is an integer number (20739316608).

Almost surely, 2^81228990001 is an apocalyptic number.

It is an amenable number.

81228990001 is a deficient number, since it is larger than the sum of its proper divisors (1728276431).

81228990001 is a wasteful number, since it uses less digits than its factorization.

81228990001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1728276430.

The product of its (nonzero) digits is 20736, while the sum is 40.

The spelling of 81228990001 in words is "eighty-one billion, two hundred twenty-eight million, nine hundred ninety thousand, one".