1661254547 has 2 divisors, whose sum is σ = 1661254548. Its totient is φ = 1661254546.

The previous prime is 1661254537. The next prime is 1661254549. The reversal of 1661254547 is 7454521661.

It is a strong prime.

It is an emirp because it is prime and its reverse (7454521661) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1661254547 - 2²⁸ = 1392819091 is a prime.

Together with 1661254549, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1661254549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830627273 + 830627274.

It is an arithmetic number, because the mean of its divisors is an integer number (830627274).

Almost surely, 2^1661254547 is an apocalyptic number.

1661254547 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661254547 is an equidigital number, since it uses as much as digits as its factorization.

1661254547 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 201600, while the sum is 41.

The square root of 1661254547 is about 40758.4904897127. The cubic root of 1661254547 is about 1184.3463543701.

The spelling of 1661254547 in words is "one billion, six hundred sixty-one million, two hundred fifty-four thousand, five hundred forty-seven".