78420907 has 4 divisors (see below), whose sum is σ = 79495240. Its totient is φ = 77346576.

The previous prime is 78420889. The next prime is 78420931. The reversal of 78420907 is 70902487.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 70902487 = 31 ⋅2287177.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78420907 is a prime.

It is a super-2 number, since 2×78420907² = 12299677309405298, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78420977) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 537057 + ... + 537202.

It is an arithmetic number, because the mean of its divisors is an integer number (19873810).

Almost surely, 2^78420907 is an apocalyptic number.

78420907 is a deficient number, since it is larger than the sum of its proper divisors (1074333).

78420907 is a wasteful number, since it uses less digits than its factorization.

78420907 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1074332.

The product of its (nonzero) digits is 28224, while the sum is 37.

The square root of 78420907 is about 8855.5579722567. The cubic root of 78420907 is about 428.0330334506.

The spelling of 78420907 in words is "seventy-eight million, four hundred twenty thousand, nine hundred seven".