1661051664 has 40 divisors (see below), whose sum is σ = 4767834720. Its totient is φ = 553683744.

The previous prime is 1661051653. The next prime is 1661051671. The reversal of 1661051664 is 4661501661.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

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, 1922082 + ... + 1922945.

It is an arithmetic number, because the mean of its divisors is an integer number (119195868).

Almost surely, 2^1661051664 is an apocalyptic number.

It is an amenable number.

1661051664 is an abundant number, since it is smaller than the sum of its proper divisors (3106783056).

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

1661051664 is a wasteful number, since it uses less digits than its factorization.

1661051664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3845044 (or 3845032 counting only the distinct ones).

The product of its (nonzero) digits is 25920, while the sum is 36.

The square root of 1661051664 is about 40756.0015703209. The cubic root of 1661051664 is about 1184.2981390973.

The spelling of 1661051664 in words is "one billion, six hundred sixty-one million, fifty-one thousand, six hundred sixty-four".