77631891 has 8 divisors (see below), whose sum is σ = 108957120. Its totient is φ = 49030632.

The previous prime is 77631889. The next prime is 77631907. The reversal of 77631891 is 19813677.

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

It is not a de Polignac number, because 77631891 - 2¹ = 77631889 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (77631391) 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, 680925 + ... + 681038.

It is an arithmetic number, because the mean of its divisors is an integer number (13619640).

Almost surely, 2^77631891 is an apocalyptic number.

77631891 is the 5573-rd centered pentagonal number.

77631891 is a deficient number, since it is larger than the sum of its proper divisors (31325229).

77631891 is a wasteful number, since it uses less digits than its factorization.

77631891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1361985.

The product of its digits is 63504, while the sum is 42.

The square root of 77631891 is about 8810.8961519246. The cubic root of 77631891 is about 426.5926695268.

The spelling of 77631891 in words is "seventy-seven million, six hundred thirty-one thousand, eight hundred ninety-one".