81690122 has 16 divisors (see below), whose sum is σ = 125854344. Its totient is φ = 39744000.

The previous prime is 81690107. The next prime is 81690137. The reversal of 81690122 is 22109618.

It is an interprime number because it is at equal distance from previous prime (81690107) and next prime (81690137).

It can be written as a sum of positive squares in 4 ways, for example, as 47596201 + 34093921 = 6899^2 + 5839^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36722 + ... + 38882.

Almost surely, 2^81690122 is an apocalyptic number.

81690122 is a gapful number since it is divisible by the number (82) formed by its first and last digit.

81690122 is a deficient number, since it is larger than the sum of its proper divisors (44164222).

81690122 is a wasteful number, since it uses less digits than its factorization.

81690122 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2665.

The product of its (nonzero) digits is 1728, while the sum is 29.

The square root of 81690122 is about 9038.2587924887. The cubic root of 81690122 is about 433.9001979098.

The spelling of 81690122 in words is "eighty-one million, six hundred ninety thousand, one hundred twenty-two".