28837531511981 has 2 divisors, whose sum is σ = 28837531511982. Its totient is φ = 28837531511980.

The previous prime is 28837531511977. The next prime is 28837531511989. The reversal of 28837531511981 is 18911513573882.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28533053789956 + 304477722025 = 5341634^2 + 551795^2 .

It is a cyclic number.

It is not a de Polignac number, because 28837531511981 - 2² = 28837531511977 is a prime.

It is a super-2 number, since 2×28837531511981² (a number of 28 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28837531511989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14418765755990 + 14418765755991.

It is an arithmetic number, because the mean of its divisors is an integer number (14418765755991).

Almost surely, 2^{28837531511981} is an apocalyptic number.

It is an amenable number.

28837531511981 is a deficient number, since it is larger than the sum of its proper divisors (1).

28837531511981 is an equidigital number, since it uses as much as digits as its factorization.

28837531511981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14515200, while the sum is 62.

The spelling of 28837531511981 in words is "twenty-eight trillion, eight hundred thirty-seven billion, five hundred thirty-one million, five hundred eleven thousand, nine hundred eighty-one".