71521801 has 8 divisors (see below), whose sum is σ = 79679880. Its totient is φ = 63743232.

The previous prime is 71521799. The next prime is 71521843. The reversal of 71521801 is 10812517.

It can be written as a sum of positive squares in 4 ways, for example, as 102400 + 71419401 = 320^2 + 8451^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 71521801 - 2¹ = 71521799 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71521001) 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, 94480 + ... + 95233.

It is an arithmetic number, because the mean of its divisors is an integer number (9959985).

Almost surely, 2^71521801 is an apocalyptic number.

It is an amenable number.

71521801 is a deficient number, since it is larger than the sum of its proper divisors (8158079).

71521801 is a wasteful number, since it uses less digits than its factorization.

71521801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 189755.

The product of its (nonzero) digits is 560, while the sum is 25.

The square root of 71521801 is about 8457.0562845472. The cubic root of 71521801 is about 415.0937050705.

The spelling of 71521801 in words is "seventy-one million, five hundred twenty-one thousand, eight hundred one".