1661254537 has 2 divisors, whose sum is σ = 1661254538. Its totient is φ = 1661254536.

The previous prime is 1661254459. The next prime is 1661254547. The reversal of 1661254537 is 7354521661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1323577161 + 337677376 = 36381^2 + 18376^2 .

It is a cyclic number.

It is not a de Polignac number, because 1661254537 - 2⁷ = 1661254409 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1661254537.

It is not a weakly prime, because it can be changed into another prime (1661254547) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830627268 + 830627269.

It is an arithmetic number, because the mean of its divisors is an integer number (830627269).

Almost surely, 2^1661254537 is an apocalyptic number.

It is an amenable number.

1661254537 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661254537 is an equidigital number, since it uses as much as digits as its factorization.

1661254537 is an evil number, because the sum of its binary digits is even.

The product of its digits is 151200, while the sum is 40.

The square root of 1661254537 is about 40758.4903670389. The cubic root of 1661254537 is about 1184.3463519937.

The spelling of 1661254537 in words is "one billion, six hundred sixty-one million, two hundred fifty-four thousand, five hundred thirty-seven".