77921651949 has 8 divisors (see below), whose sum is σ = 103938424512. Its totient is φ = 51926323680.

The previous prime is 77921651939. The next prime is 77921651957. The reversal of 77921651949 is 94915612977.

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

It is not a de Polignac number, because 77921651949 - 2²⁰ = 77920603373 is a prime.

It is a super-2 number, since 2×77921651949² (a number of 23 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 77921651892 and 77921651901.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77921651939) 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, 5352592 + ... + 5367129.

It is an arithmetic number, because the mean of its divisors is an integer number (12992303064).

Almost surely, 2^77921651949 is an apocalyptic number.

It is an amenable number.

77921651949 is a deficient number, since it is larger than the sum of its proper divisors (26016772563).

77921651949 is a wasteful number, since it uses less digits than its factorization.

77921651949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10722147.

The product of its digits is 8573040, while the sum is 60.

The spelling of 77921651949 in words is "seventy-seven billion, nine hundred twenty-one million, six hundred fifty-one thousand, nine hundred forty-nine".