5621129721 has 24 divisors (see below), whose sum is σ = 8422086816. Its totient is φ = 3610111680.

The previous prime is 5621129719. The next prime is 5621129741. The reversal of 5621129721 is 1279211265.

5621129721 is a `hidden beast` number, since 5 + 621 + 1 + 2 + 9 + 7 + 21 = 666.

5621129721 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 5621129721 - 2¹ = 5621129719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (5621129741) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 71235 + ... + 127736.

It is an arithmetic number, because the mean of its divisors is an integer number (350920284).

Almost surely, 2^5621129721 is an apocalyptic number.

It is an amenable number.

5621129721 is a deficient number, since it is larger than the sum of its proper divisors (2800957095).

5621129721 is a wasteful number, since it uses less digits than its factorization.

5621129721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199093 (or 199090 counting only the distinct ones).

The product of its digits is 15120, while the sum is 36.

The square root of 5621129721 is about 74974.1937002326. The cubic root of 5621129721 is about 1778.0386721580.

The spelling of 5621129721 in words is "five billion, six hundred twenty-one million, one hundred twenty-nine thousand, seven hundred twenty-one".