261629940 has 96 divisors (see below), whose sum is σ = 860662656. Its totient is φ = 58544640.

The previous prime is 261629939. The next prime is 261629941. The reversal of 261629940 is 49926162.

It is an interprime number because it is at equal distance from previous prime (261629939) and next prime (261629941).

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261629941) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6667 + ... + 23826.

It is an arithmetic number, because the mean of its divisors is an integer number (8965236).

Almost surely, 2^261629940 is an apocalyptic number.

261629940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261629940 is an abundant number, since it is smaller than the sum of its proper divisors (599032716).

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

261629940 is a wasteful number, since it uses less digits than its factorization.

261629940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30529 (or 30527 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 39.

The square root of 261629940 is about 16174.9788253339. The cubic root of 261629940 is about 639.5813831481.

The spelling of 261629940 in words is "two hundred sixty-one million, six hundred twenty-nine thousand, nine hundred forty".