81788701 has 2 divisors, whose sum is σ = 81788702. Its totient is φ = 81788700.

The previous prime is 81788677. The next prime is 81788741. The reversal of 81788701 is 10788718.

It is an a-pointer prime, because the next prime (81788741) can be obtained adding 81788701 to its sum of digits (40).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 70997476 + 10791225 = 8426^2 + 3285^2 .

It is a cyclic number.

It is not a de Polignac number, because 81788701 - 2¹³ = 81780509 is a prime.

It is a super-2 number, since 2×81788701² = 13378783222534802, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81788741) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40894350 + 40894351.

It is an arithmetic number, because the mean of its divisors is an integer number (40894351).

Almost surely, 2^81788701 is an apocalyptic number.

It is an amenable number.

81788701 is a deficient number, since it is larger than the sum of its proper divisors (1).

81788701 is an equidigital number, since it uses as much as digits as its factorization.

81788701 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25088, while the sum is 40.

The square root of 81788701 is about 9043.7105769701. The cubic root of 81788701 is about 434.0746631228.

The spelling of 81788701 in words is "eighty-one million, seven hundred eighty-eight thousand, seven hundred one".