71987775 has 48 divisors (see below), whose sum is σ = 127277568. Its totient is φ = 35776000.

The previous prime is 71987749. The next prime is 71987777. The reversal of 71987775 is 57778917.

It is a happy number.

It is not a de Polignac number, because 71987775 - 2⁸ = 71987519 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71987777) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 166810 + ... + 167240.

It is an arithmetic number, because the mean of its divisors is an integer number (2651616).

Almost surely, 2^71987775 is an apocalyptic number.

71987775 is a gapful number since it is divisible by the number (75) formed by its first and last digit.

71987775 is a deficient number, since it is larger than the sum of its proper divisors (55289793).

71987775 is a wasteful number, since it uses less digits than its factorization.

71987775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 592 (or 587 counting only the distinct ones).

The product of its digits is 864360, while the sum is 51.

The square root of 71987775 is about 8484.5609786246. The cubic root of 71987775 is about 415.9932178844.

The spelling of 71987775 in words is "seventy-one million, nine hundred eighty-seven thousand, seven hundred seventy-five".