3506431221 has 8 divisors (see below), whose sum is σ = 5194712960. Its totient is φ = 2337620796.

The previous prime is 3506431217. The next prime is 3506431273. The reversal of 3506431221 is 1221346053.

3506431221 is a `hidden beast` number, since 3 + 5 + 0 + 6 + 431 + 221 = 666.

It is not a de Polignac number, because 3506431221 - 2² = 3506431217 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 129867823 = 3506431221 / (3 + 5 + 0 + 6 + 4 + 3 + 1 + 2 + 2 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3506431211) 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, 64933885 + ... + 64933938.

It is an arithmetic number, because the mean of its divisors is an integer number (649339120).

Almost surely, 2^3506431221 is an apocalyptic number.

It is an amenable number.

3506431221 is a deficient number, since it is larger than the sum of its proper divisors (1688281739).

3506431221 is a wasteful number, since it uses less digits than its factorization.

3506431221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129867832 (or 129867826 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 3506431221 is about 59215.1266231864. The cubic root of 3506431221 is about 1519.2238681053.

Adding to 3506431221 its reverse (1221346053), we get a palindrome (4727777274).

The spelling of 3506431221 in words is "three billion, five hundred six million, four hundred thirty-one thousand, two hundred twenty-one".