61815487513 has 4 divisors (see below), whose sum is σ = 66570525028. Its totient is φ = 57060450000.

The previous prime is 61815487477. The next prime is 61815487523. The reversal of 61815487513 is 31578451816.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 15257931529 + 46557555984 = 123523^2 + 215772^2 .

It is a cyclic number.

It is not a de Polignac number, because 61815487513 - 2¹⁷ = 61815356441 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61815487523) 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, 2377518738 + ... + 2377518763.

It is an arithmetic number, because the mean of its divisors is an integer number (16642631257).

Almost surely, 2^61815487513 is an apocalyptic number.

It is an amenable number.

61815487513 is a deficient number, since it is larger than the sum of its proper divisors (4755037515).

61815487513 is a wasteful number, since it uses less digits than its factorization.

61815487513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4755037514.

The product of its digits is 806400, while the sum is 49.

The spelling of 61815487513 in words is "sixty-one billion, eight hundred fifteen million, four hundred eighty-seven thousand, five hundred thirteen".