1661189670 has 72 divisors (see below), whose sum is σ = 5024264544. Its totient is φ = 379699488.

The previous prime is 1661189669. The next prime is 1661189671. The reversal of 1661189670 is 769811661.

It is an interprime number because it is at equal distance from previous prime (1661189669) and next prime (1661189671).

It is a super-2 number, since 2×1661189670² = 5519102239429417800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661189671) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 183934 + ... + 192753.

It is an arithmetic number, because the mean of its divisors is an integer number (69781452).

Almost surely, 2^1661189670 is an apocalyptic number.

1661189670 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1661189670 is an abundant number, since it is smaller than the sum of its proper divisors (3363074874).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1661189670 is a wasteful number, since it uses less digits than its factorization.

1661189670 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 376714 (or 376704 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 45.

The square root of 1661189670 is about 40757.6946109566. The cubic root of 1661189670 is about 1184.3309367372.

The spelling of 1661189670 in words is "one billion, six hundred sixty-one million, one hundred eighty-nine thousand, six hundred seventy".