29957439808921 has 9 divisors (see below), whose sum is σ = 30084622882783. Its totient is φ = 29830792217800.

The previous prime is 29957439808819. The next prime is 29957439808943. The reversal of 29957439808921 is 12980893475992.

The square root of 29957439808921 is 5473339.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 29436473440521 + 520966368400 = 5425539^2 + 721780^2 .

It is not a de Polignac number, because 29957439808921 - 2¹⁷ = 29957439677849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (29957439808991) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1308116571 + ... + 1308139471.

Almost surely, 2^{29957439808921} is an apocalyptic number.

29957439808921 is the 5473339-th square number.

29957439808921 is the 2736670-th centered octagonal number.

It is an amenable number.

29957439808921 is a deficient number, since it is larger than the sum of its proper divisors (127183073862).

29957439808921 is an frugal number, since it uses more digits than its factorization.

29957439808921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46280 (or 23140 counting only the distinct ones).

The product of its (nonzero) digits is 705438720, while the sum is 76.

The spelling of 29957439808921 in words is "twenty-nine trillion, nine hundred fifty-seven billion, four hundred thirty-nine million, eight hundred eight thousand, nine hundred twenty-one".