78725561 has 8 divisors (see below), whose sum is σ = 81358464. Its totient is φ = 76129200.

The previous prime is 78725557. The next prime is 78725567. The reversal of 78725561 is 16552787.

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 78725561 - 2² = 78725557 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78725567) 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, 4721 + ... + 13406.

It is an arithmetic number, because the mean of its divisors is an integer number (10169808).

Almost surely, 2^78725561 is an apocalyptic number.

It is an amenable number.

78725561 is a deficient number, since it is larger than the sum of its proper divisors (2632903).

78725561 is a wasteful number, since it uses less digits than its factorization.

78725561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18271.

The product of its digits is 117600, while the sum is 41.

The square root of 78725561 is about 8872.7425861455. The cubic root of 78725561 is about 428.5865995846.

The spelling of 78725561 in words is "seventy-eight million, seven hundred twenty-five thousand, five hundred sixty-one".