78251961 has 4 divisors (see below), whose sum is σ = 104335952. Its totient is φ = 52167972.

The previous prime is 78251951. The next prime is 78251983. The reversal of 78251961 is 16915287.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16915287 = 3 ⋅5638429.

It is not a de Polignac number, because 78251961 - 2⁶ = 78251897 is a prime.

It is a super-2 number, since 2×78251961² = 12246738800691042, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78251941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13041991 + ... + 13041996.

It is an arithmetic number, because the mean of its divisors is an integer number (26083988).

Almost surely, 2^78251961 is an apocalyptic number.

It is an amenable number.

78251961 is a deficient number, since it is larger than the sum of its proper divisors (26083991).

78251961 is a wasteful number, since it uses less digits than its factorization.

78251961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26083990.

The product of its digits is 30240, while the sum is 39.

The square root of 78251961 is about 8846.0138480561. The cubic root of 78251961 is about 427.7254349454.

The spelling of 78251961 in words is "seventy-eight million, two hundred fifty-one thousand, nine hundred sixty-one".