661003770 has 128 divisors (see below), whose sum is σ = 1866571776. Its totient is φ = 146681856.

The previous prime is 661003769. The next prime is 661003771. The reversal of 661003770 is 77300166.

It is an interprime number because it is at equal distance from previous prime (661003769) and next prime (661003771).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (661003771) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1904737 + ... + 1905083.

It is an arithmetic number, because the mean of its divisors is an integer number (14582592).

Almost surely, 2^661003770 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661003770, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (933285888).

661003770 is an abundant number, since it is smaller than the sum of its proper divisors (1205568006).

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

661003770 is a wasteful number, since it uses less digits than its factorization.

661003770 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 604.

The product of its (nonzero) digits is 5292, while the sum is 30.

The square root of 661003770 is about 25709.9935822629. The cubic root of 661003770 is about 871.0999299649.

The spelling of 661003770 in words is "six hundred sixty-one million, three thousand, seven hundred seventy".