81439701 has 32 divisors (see below), whose sum is σ = 128249088. Its totient is φ = 44997120.

The previous prime is 81439679. The next prime is 81439703. The reversal of 81439701 is 10793418.

It is not a de Polignac number, because 81439701 - 2⁵ = 81439669 is a prime.

It is a plaindrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81439703) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 218151 + ... + 218523.

It is an arithmetic number, because the mean of its divisors is an integer number (4007784).

Almost surely, 2^81439701 is an apocalyptic number.

It is an amenable number.

81439701 is a deficient number, since it is larger than the sum of its proper divisors (46809387).

81439701 is a wasteful number, since it uses less digits than its factorization.

81439701 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 701.

The product of its (nonzero) digits is 6048, while the sum is 33.

The square root of 81439701 is about 9024.3947719501. The cubic root of 81439701 is about 433.4563705194.

The spelling of 81439701 in words is "eighty-one million, four hundred thirty-nine thousand, seven hundred one".