1651661646 has 16 divisors (see below), whose sum is σ = 3348575184. Its totient is φ = 543011904.

The previous prime is 1651661633. The next prime is 1651661647. The reversal of 1651661646 is 6461661561.

It is a junction number, because it is equal to n+sod(n) for n = 1651661598 and 1651661607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1651661647) 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, 1885021 + ... + 1885896.

It is an arithmetic number, because the mean of its divisors is an integer number (209285949).

Almost surely, 2^1651661646 is an apocalyptic number.

1651661646 is an abundant number, since it is smaller than the sum of its proper divisors (1696913538).

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

1651661646 is a wasteful number, since it uses less digits than its factorization.

1651661646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3770995.

The product of its digits is 155520, while the sum is 42.

The square root of 1651661646 is about 40640.6403246799. The cubic root of 1651661646 is about 1182.0622861065.

The spelling of 1651661646 in words is "one billion, six hundred fifty-one million, six hundred sixty-one thousand, six hundred forty-six".