78406442 has 8 divisors (see below), whose sum is σ = 117709956. Its totient is φ = 39169792.

The previous prime is 78406439. The next prime is 78406477. The reversal of 78406442 is 24460487.

It can be written as a sum of positive squares in 2 ways, for example, as 75881521 + 2524921 = 8711^2 + 1589^2 .

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

It is a super-2 number, since 2×78406442² = 12295140294198728, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13673 + ... + 18540.

Almost surely, 2^78406442 is an apocalyptic number.

78406442 is a deficient number, since it is larger than the sum of its proper divisors (39303514).

78406442 is a wasteful number, since it uses less digits than its factorization.

78406442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33432.

The product of its (nonzero) digits is 43008, while the sum is 35.

The square root of 78406442 is about 8854.7412158685. The cubic root of 78406442 is about 428.0067144549.

The spelling of 78406442 in words is "seventy-eight million, four hundred six thousand, four hundred forty-two".