261491004 has 30 divisors (see below), whose sum is σ = 683589984. Its totient is φ = 87163560.

The previous prime is 261490997. The next prime is 261491011. The reversal of 261491004 is 400194162.

261491004 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (261490997) and next prime (261491011).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 403212 + ... + 403859.

Almost surely, 2^261491004 is an apocalyptic number.

It is an amenable number.

261491004 is an abundant number, since it is smaller than the sum of its proper divisors (422098980).

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

261491004 is a wasteful number, since it uses less digits than its factorization.

261491004 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 807087 (or 807076 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 261491004 is about 16170.6834734961. The cubic root of 261491004 is about 639.4681486393.

The spelling of 261491004 in words is "two hundred sixty-one million, four hundred ninety-one thousand, four".