661001025 has 48 divisors (see below), whose sum is σ = 1149105024. Its totient is φ = 334625280.

The previous prime is 661000999. The next prime is 661001027. The reversal of 661001025 is 520100166.

It is a happy number.

It is not a de Polignac number, because 661001025 - 2¹¹ = 660998977 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 661000992 and 661001010.

It is not an unprimeable number, because it can be changed into a prime (661001027) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 234927 + ... + 237723.

It is an arithmetic number, because the mean of its divisors is an integer number (23939688).

Almost surely, 2^661001025 is an apocalyptic number.

It is an amenable number.

661001025 is a deficient number, since it is larger than the sum of its proper divisors (488103999).

661001025 is a wasteful number, since it uses less digits than its factorization.

661001025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2970 (or 2965 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 661001025 is about 25709.9401982968. The cubic root of 661001025 is about 871.0987241359.

The spelling of 661001025 in words is "six hundred sixty-one million, one thousand, twenty-five".