71821990 has 16 divisors (see below), whose sum is σ = 131210352. Its totient is φ = 28299744.

The previous prime is 71821979. The next prime is 71821993. The reversal of 71821990 is 9912817.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71821993) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52929 + ... + 54268.

It is an arithmetic number, because the mean of its divisors is an integer number (8200647).

Almost surely, 2^71821990 is an apocalyptic number.

71821990 is a deficient number, since it is larger than the sum of its proper divisors (59388362).

71821990 is a wasteful number, since it uses less digits than its factorization.

71821990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107271.

The product of its (nonzero) digits is 9072, while the sum is 37.

The square root of 71821990 is about 8474.7855430093. The cubic root of 71821990 is about 415.6736337836.

The spelling of 71821990 in words is "seventy-one million, eight hundred twenty-one thousand, nine hundred ninety".