7821211977 has 12 divisors (see below), whose sum is σ = 11326808064.
Its totient is φ = 5200525080.
The previous prime is 7821211949. The next prime is 7821212011. The reversal of 7821211977 is 7791121287.
It is not a de Polignac number, because 7821211977 - 220 = 7820163401 is a prime.
It is a super-2 number, since 2×78212119772 (a number of 21 digits) contains 22 as substring.
It is not an unprimeable number, because it can be changed into a prime (7821211577) by changing a digit.
It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1131049 + ... + 1137942.
It is an arithmetic number, because the mean of its divisors is an integer number (943900672).
Almost surely, 27821211977 is an apocalyptic number.
It is an amenable number.
7821211977 is a deficient number, since it is larger than the sum of its proper divisors (3505596087).
7821211977 is a wasteful number, since it uses less digits than its factorization.
7821211977 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 2269380 (or 2269377 counting only the distinct ones).
The product of its digits is 98784, while the sum is 45.
The square root of 7821211977 is about 88437.6163009836.
The cubic root of 7821211977 is about 1984.9886090454.
The spelling of 7821211977 in words is "seven billion, eight hundred twenty-one million, two hundred eleven thousand, nine hundred seventy-seven".