78505505501 has 4 divisors (see below), whose sum is σ = 78810974652. Its totient is φ = 78200036352.

The previous prime is 78505505489. The next prime is 78505505539. The reversal of 78505505501 is 10550550587.

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 2 ways, for example, as 67638485476 + 10867020025 = 260074^2 + 104245^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78505505501 is a prime.

It is a super-2 number, since 2×78505505501² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78505505581) 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, 152734190 + ... + 152734703.

It is an arithmetic number, because the mean of its divisors is an integer number (19702743663).

Almost surely, 2^78505505501 is an apocalyptic number.

It is an amenable number.

78505505501 is a deficient number, since it is larger than the sum of its proper divisors (305469151).

78505505501 is a wasteful number, since it uses less digits than its factorization.

78505505501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 305469150.

The product of its (nonzero) digits is 175000, while the sum is 41.

The spelling of 78505505501 in words is "seventy-eight billion, five hundred five million, five hundred five thousand, five hundred one".