1661254538 has 8 divisors (see below), whose sum is σ = 2492529732. Its totient is φ = 830411296.

The previous prime is 1661254537. The next prime is 1661254547. The reversal of 1661254538 is 8354521661.

It can be written as a sum of positive squares in 2 ways, for example, as 1655431969 + 5822569 = 40687^2 + 2413^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 1661254495 and 1661254504.

It is not an unprimeable number, because it can be changed into a prime (1661254537) 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, 98195 + ... + 113862.

Almost surely, 2^1661254538 is an apocalyptic number.

1661254538 is a deficient number, since it is larger than the sum of its proper divisors (831275194).

1661254538 is a wasteful number, since it uses less digits than its factorization.

1661254538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215976.

The product of its digits is 172800, while the sum is 41.

The square root of 1661254538 is about 40758.4903793062. The cubic root of 1661254538 is about 1184.3463522314.

The spelling of 1661254538 in words is "one billion, six hundred sixty-one million, two hundred fifty-four thousand, five hundred thirty-eight".