78151681 has 8 divisors (see below), whose sum is σ = 79468064. Its totient is φ = 76839840.

The previous prime is 78151649. The next prime is 78151709. The reversal of 78151681 is 18615187.

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 78151681 - 2⁵ = 78151649 is a prime.

It is a super-2 number, since 2×78151681² = 12215370486251522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 78151681.

It is not an unprimeable number, because it can be changed into a prime (78151981) 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, 58501 + ... + 59821.

It is an arithmetic number, because the mean of its divisors is an integer number (9933508).

It is a Proth number, since it is equal to 2385 ⋅ 2¹⁵ + 1 and 2385 < 2¹⁵.

Almost surely, 2^78151681 is an apocalyptic number.

It is an amenable number.

78151681 is a deficient number, since it is larger than the sum of its proper divisors (1316383).

78151681 is a wasteful number, since it uses less digits than its factorization.

78151681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2271.

The product of its digits is 13440, while the sum is 37.

The square root of 78151681 is about 8840.3439412729. The cubic root of 78151681 is about 427.5426465896.

The spelling of 78151681 in words is "seventy-eight million, one hundred fifty-one thousand, six hundred eighty-one".