1661025004 has 12 divisors (see below), whose sum is σ = 2907613800. Its totient is φ = 830278208.

The previous prime is 1661024987. The next prime is 1661025019. The reversal of 1661025004 is 4005201661.

It is a self number, because there is not a number n which added to its sum of digits gives 1661025004.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42109 + ... + 71380.

It is an arithmetic number, because the mean of its divisors is an integer number (242301150).

Almost surely, 2^1661025004 is an apocalyptic number.

It is an amenable number.

1661025004 is a deficient number, since it is larger than the sum of its proper divisors (1246588796).

1661025004 is a wasteful number, since it uses less digits than its factorization.

1661025004 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117152 (or 117150 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 1661025004 is about 40755.6745006140. The cubic root of 1661025004 is about 1184.2918030397.

Adding to 1661025004 its reverse (4005201661), we get a palindrome (5666226665).

It can be divided in two parts, 16610 and 25004, that added together give a palindrome (41614).

The spelling of 1661025004 in words is "one billion, six hundred sixty-one million, twenty-five thousand, four".