71209440 has 72 divisors (see below), whose sum is σ = 243007128. Its totient is φ = 18988800.

The previous prime is 71209433. The next prime is 71209483. The reversal of 71209440 is 4490217.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (72).

It is a super-2 number, since 2×71209440² = 10141568690227200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 23286 + ... + 26165.

It is an arithmetic number, because the mean of its divisors is an integer number (3375099).

Almost surely, 2^71209440 is an apocalyptic number.

It is an amenable number.

71209440 is an abundant number, since it is smaller than the sum of its proper divisors (171797688).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

71209440 is a wasteful number, since it uses less digits than its factorization.

71209440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49472 (or 49461 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 71209440 is about 8438.5685989983. The cubic root of 71209440 is about 414.4885362128.

Adding to 71209440 its reverse (4490217), we get a palindrome (75699657).

The spelling of 71209440 in words is "seventy-one million, two hundred nine thousand, four hundred forty".