78149453721 has 8 divisors (see below), whose sum is σ = 107792350080. Its totient is φ = 50303096592.

The previous prime is 78149453677. The next prime is 78149453801. The reversal of 78149453721 is 12735494187.

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

It is not a de Polignac number, because 78149453721 - 2⁷ = 78149453593 is a prime.

It is a super-2 number, since 2×78149453721² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78149453021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 449134705 + ... + 449134878.

It is an arithmetic number, because the mean of its divisors is an integer number (13474043760).

Almost surely, 2^78149453721 is an apocalyptic number.

It is an amenable number.

78149453721 is a deficient number, since it is larger than the sum of its proper divisors (29642896359).

78149453721 is a wasteful number, since it uses less digits than its factorization.

78149453721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 898269615.

The product of its digits is 1693440, while the sum is 51.

The spelling of 78149453721 in words is "seventy-eight billion, one hundred forty-nine million, four hundred fifty-three thousand, seven hundred twenty-one".