1661629440 has 88 divisors (see below), whose sum is σ = 5314667040. Its totient is φ = 443097088.

The previous prime is 1661629433. The next prime is 1661629451. The reversal of 1661629440 is 449261661.

It is a super-3 number, since 3×1661629440³ (a number of 29 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38730 + ... + 69449.

Almost surely, 2^1661629440 is an apocalyptic number.

1661629440 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1661629440 is an abundant number, since it is smaller than the sum of its proper divisors (3653037600).

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

1661629440 is a wasteful number, since it uses less digits than its factorization.

1661629440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108207 (or 108189 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 39.

The square root of 1661629440 is about 40763.0891861743. The cubic root of 1661629440 is about 1184.4354376002.

It can be divided in two parts, 16616 and 29440, that added together give a triangular number (46056 = T₃₀₃).

The spelling of 1661629440 in words is "one billion, six hundred sixty-one million, six hundred twenty-nine thousand, four hundred forty".