261721488 has 40 divisors (see below), whose sum is σ = 772702528. Its totient is φ = 74777472.

The previous prime is 261721487. The next prime is 261721501. The reversal of 261721488 is 884127162.

It is a happy number.

261721488 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (261721487) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 389131 + ... + 389802.

Almost surely, 2^261721488 is an apocalyptic number.

261721488 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

261721488 is an abundant number, since it is smaller than the sum of its proper divisors (510981040).

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

261721488 is a wasteful number, since it uses less digits than its factorization.

261721488 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 778951 (or 778945 counting only the distinct ones).

The product of its digits is 43008, while the sum is 39.

The square root of 261721488 is about 16177.8085042443. The cubic root of 261721488 is about 639.6559739593.

The spelling of 261721488 in words is "two hundred sixty-one million, seven hundred twenty-one thousand, four hundred eighty-eight".