71978077 has 2 divisors, whose sum is σ = 71978078. Its totient is φ = 71978076.

The previous prime is 71978059. The next prime is 71978107. The reversal of 71978077 is 77087917.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 70375321 + 1602756 = 8389^2 + 1266^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-71978077 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (71978057) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 35989038 + 35989039.

It is an arithmetic number, because the mean of its divisors is an integer number (35989039).

Almost surely, 2^71978077 is an apocalyptic number.

It is an amenable number.

71978077 is a deficient number, since it is larger than the sum of its proper divisors (1).

71978077 is an equidigital number, since it uses as much as digits as its factorization.

71978077 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 172872, while the sum is 46.

The square root of 71978077 is about 8483.9894507242. The cubic root of 71978077 is about 415.9745365485.

The spelling of 71978077 in words is "seventy-one million, nine hundred seventy-eight thousand, seventy-seven".