81629942 has 4 divisors (see below), whose sum is σ = 122444916. Its totient is φ = 40814970.

The previous prime is 81629941. The next prime is 81629959. The reversal of 81629942 is 24992618.

It is a semiprime because it is the product of two primes.

It is a self number, because there is not a number n which added to its sum of digits gives 81629942.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81629941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20407484 + ... + 20407487.

It is an arithmetic number, because the mean of its divisors is an integer number (30611229).

Almost surely, 2^81629942 is an apocalyptic number.

81629942 is a deficient number, since it is larger than the sum of its proper divisors (40814974).

81629942 is a wasteful number, since it uses less digits than its factorization.

81629942 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40814973.

The product of its digits is 62208, while the sum is 41.

The square root of 81629942 is about 9034.9289980608. The cubic root of 81629942 is about 433.7936222796.

The spelling of 81629942 in words is "eighty-one million, six hundred twenty-nine thousand, nine hundred forty-two".