20612057761 has 3 divisors (see below), whose sum is σ = 20612201331. Its totient is φ = 20611914192.

The previous prime is 20612057737. The next prime is 20612057773. The reversal of 20612057761 is 16775021602.

The square root of 20612057761 is 143569.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 2613152161 + 17998905600 = 51119^2 + 134160^2 .

It is not a de Polignac number, because 20612057761 - 2¹³ = 20612049569 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20612057761.

It is not an unprimeable number, because it can be changed into a prime (20612057701) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 71785 + ... + 215353.

It is an arithmetic number, because the mean of its divisors is an integer number (6870733777).

Almost surely, 2^20612057761 is an apocalyptic number.

20612057761 is the 143569-th square number.

20612057761 is the 71785-th centered octagonal number.

It is an amenable number.

20612057761 is a deficient number, since it is larger than the sum of its proper divisors (143570).

20612057761 is an frugal number, since it uses more digits than its factorization.

20612057761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 287138 (or 143569 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 37.

The spelling of 20612057761 in words is "twenty billion, six hundred twelve million, fifty-seven thousand, seven hundred sixty-one".