29537921981 has 2 divisors, whose sum is σ = 29537921982. Its totient is φ = 29537921980.

The previous prime is 29537921887. The next prime is 29537922047. The reversal of 29537921981 is 18912973592.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 29537921956 + 25 = 171866^2 + 5^2 .

It is a cyclic number.

It is not a de Polignac number, because 29537921981 - 2²² = 29533727677 is a prime.

It is a super-2 number, since 2×29537921981² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (29537923981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14768960990 + 14768960991.

It is an arithmetic number, because the mean of its divisors is an integer number (14768960991).

Almost surely, 2^29537921981 is an apocalyptic number.

It is an amenable number.

29537921981 is a deficient number, since it is larger than the sum of its proper divisors (1).

29537921981 is an equidigital number, since it uses as much as digits as its factorization.

29537921981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2449440, while the sum is 56.

The spelling of 29537921981 in words is "twenty-nine billion, five hundred thirty-seven million, nine hundred twenty-one thousand, nine hundred eighty-one".