1642761961 has 3 divisors (see below), whose sum is σ = 1642802493. Its totient is φ = 1642721430.

The previous prime is 1642761943. The next prime is 1642762031. The reversal of 1642761961 is 1691672461.

The square root of 1642761961 is 40531.

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, and also an emirpimes, since its reverse is a distinct semiprime: 1691672461 = 107 ⋅15810023.

It is not a de Polignac number, because 1642761961 - 2¹³ = 1642753769 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1642761761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 20266 + ... + 60796.

It is an arithmetic number, because the mean of its divisors is an integer number (547600831).

Almost surely, 2^1642761961 is an apocalyptic number.

1642761961 is the 40531-st square number.

1642761961 is the 20266-th centered octagonal number.

It is an amenable number.

1642761961 is a deficient number, since it is larger than the sum of its proper divisors (40532).

1642761961 is an frugal number, since it uses more digits than its factorization.

1642761961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81062 (or 40531 counting only the distinct ones).

The product of its digits is 108864, while the sum is 43.

The cubic root of 1642761961 is about 1179.9353505230.

The spelling of 1642761961 in words is "one billion, six hundred forty-two million, seven hundred sixty-one thousand, nine hundred sixty-one".