77513215021 has 16 divisors (see below), whose sum is σ = 87507629568. Its totient is φ = 68021553600.

The previous prime is 77513214997. The next prime is 77513215049. The reversal of 77513215021 is 12051231577.

It is not a de Polignac number, because 77513215021 - 2⁷ = 77513214893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77513215621) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 150910 + ... + 421663.

It is an arithmetic number, because the mean of its divisors is an integer number (5469226848).

Almost surely, 2^77513215021 is an apocalyptic number.

It is an amenable number.

77513215021 is a deficient number, since it is larger than the sum of its proper divisors (9994414547).

77513215021 is a wasteful number, since it uses less digits than its factorization.

77513215021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 573012.

The product of its (nonzero) digits is 14700, while the sum is 34.

Adding to 77513215021 its reverse (12051231577), we get a palindrome (89564446598).

The spelling of 77513215021 in words is "seventy-seven billion, five hundred thirteen million, two hundred fifteen thousand, twenty-one".