71521901 has 4 divisors (see below), whose sum is σ = 78023904. Its totient is φ = 65019900.

The previous prime is 71521843. The next prime is 71521949. The reversal of 71521901 is 10912517.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 71521901 - 2¹⁰ = 71520877 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71521001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3250985 + ... + 3251006.

It is an arithmetic number, because the mean of its divisors is an integer number (19505976).

Almost surely, 2^71521901 is an apocalyptic number.

It is an amenable number.

71521901 is a deficient number, since it is larger than the sum of its proper divisors (6502003).

71521901 is a wasteful number, since it uses less digits than its factorization.

71521901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6502002.

The product of its (nonzero) digits is 630, while the sum is 26.

The square root of 71521901 is about 8457.0621967679. The cubic root of 71521901 is about 415.0938985283.

The spelling of 71521901 in words is "seventy-one million, five hundred twenty-one thousand, nine hundred one".