71937821 has 4 divisors (see below), whose sum is σ = 73692444. Its totient is φ = 70183200.

The previous prime is 71937799. The next prime is 71937841. The reversal of 71937821 is 12873917.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9369721 + 62568100 = 3061^2 + 7910^2 .

It is a cyclic number.

It is not a de Polignac number, because 71937821 - 2⁶ = 71937757 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71937841) 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, 877250 + ... + 877331.

It is an arithmetic number, because the mean of its divisors is an integer number (18423111).

Almost surely, 2^71937821 is an apocalyptic number.

It is an amenable number.

71937821 is a deficient number, since it is larger than the sum of its proper divisors (1754623).

71937821 is a wasteful number, since it uses less digits than its factorization.

71937821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1754622.

The product of its digits is 21168, while the sum is 38.

The square root of 71937821 is about 8481.6166501440. The cubic root of 71937821 is about 415.8969731458.

The spelling of 71937821 in words is "seventy-one million, nine hundred thirty-seven thousand, eight hundred twenty-one".