1821752661 has 8 divisors (see below), whose sum is σ = 2556845920. Its totient is φ = 1150580592.

The previous prime is 1821752633. The next prime is 1821752677. The reversal of 1821752661 is 1662571281.

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

It is not a de Polignac number, because 1821752661 - 2⁷ = 1821752533 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1821750661) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15980230 + ... + 15980343.

It is an arithmetic number, because the mean of its divisors is an integer number (319605740).

Almost surely, 2^1821752661 is an apocalyptic number.

It is an amenable number.

1821752661 is a deficient number, since it is larger than the sum of its proper divisors (735093259).

1821752661 is a wasteful number, since it uses less digits than its factorization.

1821752661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31960595.

The product of its digits is 40320, while the sum is 39.

The square root of 1821752661 is about 42681.9945761676. The cubic root of 1821752661 is about 1221.3209424888.

The spelling of 1821752661 in words is "one billion, eight hundred twenty-one million, seven hundred fifty-two thousand, six hundred sixty-one".