721131651 has 12 divisors (see below), whose sum is σ = 1042039128. Its totient is φ = 480567744.

The previous prime is 721131647. The next prime is 721131713. The reversal of 721131651 is 156131127.

721131651 is a `hidden beast` number, since 7 + 2 + 1 + 1 + 3 + 1 + 651 = 666.

It is not a de Polignac number, because 721131651 - 2² = 721131647 is a prime.

It is not an unprimeable number, because it can be changed into a prime (721131611) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 11356 + ... + 39638.

It is an arithmetic number, because the mean of its divisors is an integer number (86836594).

Almost surely, 2^721131651 is an apocalyptic number.

721131651 is a deficient number, since it is larger than the sum of its proper divisors (320907477).

721131651 is a wasteful number, since it uses less digits than its factorization.

721131651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31122 (or 31119 counting only the distinct ones).

The product of its digits is 1260, while the sum is 27.

The square root of 721131651 is about 26853.8945220242. The cubic root of 721131651 is about 896.7502763038.

Adding to 721131651 its reverse (156131127), we get a palindrome (877262778).

The spelling of 721131651 in words is "seven hundred twenty-one million, one hundred thirty-one thousand, six hundred fifty-one".