820729987 has 8 divisors (see below), whose sum is σ = 1023247872. Its totient is φ = 639529800.

The previous prime is 820729981. The next prime is 820730003. The reversal of 820729987 is 789927028.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-820729987 is a prime.

It is a super-2 number, since 2×820729987² = 1347195423122040338, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (820729981) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5329339 + ... + 5329492.

It is an arithmetic number, because the mean of its divisors is an integer number (127905984).

Almost surely, 2^820729987 is an apocalyptic number.

820729987 is a deficient number, since it is larger than the sum of its proper divisors (202517885).

820729987 is a wasteful number, since it uses less digits than its factorization.

820729987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10658849.

The product of its (nonzero) digits is 1016064, while the sum is 52.

The square root of 820729987 is about 28648.3854169829. The cubic root of 820729987 is about 936.2678281671.

The spelling of 820729987 in words is "eight hundred twenty million, seven hundred twenty-nine thousand, nine hundred eighty-seven".