78401615 has 8 divisors (see below), whose sum is σ = 94441248. Its totient is φ = 62481760.

The previous prime is 78401611. The next prime is 78401627. The reversal of 78401615 is 51610487.

It is a happy number.

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

It is not a de Polignac number, because 78401615 - 2² = 78401611 is a prime.

It is a super-2 number, since 2×78401615² = 12293626469216450, which 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 (78401611) 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, 28496 + ... + 31125.

It is an arithmetic number, because the mean of its divisors is an integer number (11805156).

Almost surely, 2^78401615 is an apocalyptic number.

78401615 is a deficient number, since it is larger than the sum of its proper divisors (16039633).

78401615 is a wasteful number, since it uses less digits than its factorization.

78401615 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59889.

The product of its (nonzero) digits is 6720, while the sum is 32.

The square root of 78401615 is about 8854.4686458308. The cubic root of 78401615 is about 427.9979310320.

The spelling of 78401615 in words is "seventy-eight million, four hundred one thousand, six hundred fifteen".