81629739 has 6 divisors (see below), whose sum is σ = 117909636. Its totient is φ = 54419820.

The previous prime is 81629707. The next prime is 81629749. The reversal of 81629739 is 93792618.

It is not a de Polignac number, because 81629739 - 2⁵ = 81629707 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81629694 and 81629703.

It is not an unprimeable number, because it can be changed into a prime (81629749) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4534977 + ... + 4534994.

It is an arithmetic number, because the mean of its divisors is an integer number (19651606).

Almost surely, 2^81629739 is an apocalyptic number.

81629739 is a deficient number, since it is larger than the sum of its proper divisors (36279897).

81629739 is a wasteful number, since it uses less digits than its factorization.

81629739 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9069977 (or 9069974 counting only the distinct ones).

The product of its digits is 163296, while the sum is 45.

The square root of 81629739 is about 9034.9177638759. The cubic root of 81629739 is about 433.7932626886.

The spelling of 81629739 in words is "eighty-one million, six hundred twenty-nine thousand, seven hundred thirty-nine".