1661651004 has 96 divisors (see below), whose sum is σ = 4445280000. Its totient is φ = 478849536.

The previous prime is 1661650997. The next prime is 1661651051. The reversal of 1661651004 is 4001561661.

It is a super-2 number, since 2×1661651004² = 5522168118188416032, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 260647 + ... + 266945.

It is an arithmetic number, because the mean of its divisors is an integer number (46305000).

Almost surely, 2^1661651004 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1661651004, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2222640000).

1661651004 is an abundant number, since it is smaller than the sum of its proper divisors (2783628996).

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

1661651004 is a wasteful number, since it uses less digits than its factorization.

1661651004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6427 (or 6425 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 30.

The square root of 1661651004 is about 40763.3536893127. The cubic root of 1661651004 is about 1184.4405612968.

The spelling of 1661651004 in words is "one billion, six hundred sixty-one million, six hundred fifty-one thousand, four".