81490069 has 4 divisors (see below), whose sum is σ = 85779040. Its totient is φ = 77201100.

The previous prime is 81490067. The next prime is 81490109. The reversal of 81490069 is 96009418.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81490069 - 2¹ = 81490067 is a prime.

It is a super-2 number, since 2×81490069² = 13281262691249522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81490067) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2144457 + ... + 2144494.

It is an arithmetic number, because the mean of its divisors is an integer number (21444760).

Almost surely, 2^81490069 is an apocalyptic number.

It is an amenable number.

81490069 is a deficient number, since it is larger than the sum of its proper divisors (4288971).

81490069 is a wasteful number, since it uses less digits than its factorization.

81490069 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4288970.

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 81490069 is about 9027.1849986582. The cubic root of 81490069 is about 433.5457120031.

The spelling of 81490069 in words is "eighty-one million, four hundred ninety thousand, sixty-nine".