816371721755 has 8 divisors (see below), whose sum is σ = 1022239373472. Its totient is φ = 624701839168.

The previous prime is 816371721703. The next prime is 816371721761. The reversal of 816371721755 is 557127173618.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 816371721755 - 2⁶ = 816371721691 is a prime.

It is a super-3 number, since 3×816371721755³ (a number of 37 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 816371721697 and 816371721706.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3549442154 + ... + 3549442383.

It is an arithmetic number, because the mean of its divisors is an integer number (127779921684).

Almost surely, 2^816371721755 is an apocalyptic number.

816371721755 is a deficient number, since it is larger than the sum of its proper divisors (205867651717).

816371721755 is a wasteful number, since it uses less digits than its factorization.

816371721755 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7098884565.

The product of its digits is 2469600, while the sum is 53.

The spelling of 816371721755 in words is "eight hundred sixteen billion, three hundred seventy-one million, seven hundred twenty-one thousand, seven hundred fifty-five".