81421660498 has 4 divisors (see below), whose sum is σ = 122132490750. Its totient is φ = 40710830248.

The previous prime is 81421660493. The next prime is 81421660501. The reversal of 81421660498 is 89406612418.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 79539228729 + 1882431769 = 282027^2 + 43387^2 .

It is not an unprimeable number, because it can be changed into a prime (81421660493) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20355415123 + ... + 20355415126.

Almost surely, 2^81421660498 is an apocalyptic number.

81421660498 is a deficient number, since it is larger than the sum of its proper divisors (40710830252).

81421660498 is a wasteful number, since it uses less digits than its factorization.

81421660498 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40710830251.

The product of its (nonzero) digits is 663552, while the sum is 49.

The spelling of 81421660498 in words is "eighty-one billion, four hundred twenty-one million, six hundred sixty thousand, four hundred ninety-eight".