79007821 has 4 divisors (see below), whose sum is σ = 80008000. Its totient is φ = 78007644.

The previous prime is 79007801. The next prime is 79007869. The reversal of 79007821 is 12870097.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12870097 = 67 ⋅192091.

It is a cyclic number.

It is not a de Polignac number, because 79007821 - 2⁷ = 79007693 is a prime.

It is a Duffinian number.

79007821 is a modest number, since divided by 7821 gives 79 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79007801) 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, 499971 + ... + 500128.

It is an arithmetic number, because the mean of its divisors is an integer number (20002000).

Almost surely, 2^79007821 is an apocalyptic number.

It is an amenable number.

79007821 is a deficient number, since it is larger than the sum of its proper divisors (1000179).

79007821 is a wasteful number, since it uses less digits than its factorization.

79007821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1000178.

The product of its (nonzero) digits is 7056, while the sum is 34.

The square root of 79007821 is about 8888.6343720506. The cubic root of 79007821 is about 429.0982020088.

The spelling of 79007821 in words is "seventy-nine million, seven thousand, eight hundred twenty-one".