261905004 has 36 divisors (see below), whose sum is σ = 662557896. Its totient is φ = 87233088.

The previous prime is 261904997. The next prime is 261905011. The reversal of 261905004 is 400509162.

It is an interprime number because it is at equal distance from previous prime (261904997) and next prime (261905011).

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×261905004² = 137188462240480032, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 66967 + ... + 70769.

It is an arithmetic number, because the mean of its divisors is an integer number (18404386).

Almost surely, 2^261905004 is an apocalyptic number.

It is an amenable number.

261905004 is an abundant number, since it is smaller than the sum of its proper divisors (400652892).

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

261905004 is a wasteful number, since it uses less digits than its factorization.

261905004 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5726 (or 5721 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 261905004 is about 16183.4793539585. The cubic root of 261905004 is about 639.8054454203.

The spelling of 261905004 in words is "two hundred sixty-one million, nine hundred five thousand, four".