81937469 has 2 divisors, whose sum is σ = 81937470. Its totient is φ = 81937468.

The previous prime is 81937459. The next prime is 81937483. The reversal of 81937469 is 96473918.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81902500 + 34969 = 9050^2 + 187^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81937469 is a prime.

It is a super-2 number, since 2×81937469² = 13427497652251922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81937439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40968734 + 40968735.

It is an arithmetic number, because the mean of its divisors is an integer number (40968735).

Almost surely, 2^81937469 is an apocalyptic number.

It is an amenable number.

81937469 is a deficient number, since it is larger than the sum of its proper divisors (1).

81937469 is an equidigital number, since it uses as much as digits as its factorization.

81937469 is an evil number, because the sum of its binary digits is even.

The product of its digits is 326592, while the sum is 47.

The square root of 81937469 is about 9051.9317827743. The cubic root of 81937469 is about 434.3376876599.

The spelling of 81937469 in words is "eighty-one million, nine hundred thirty-seven thousand, four hundred sixty-nine".