261211577660 has 24 divisors (see below), whose sum is σ = 598411978416. Its totient is φ = 94986028160.

The previous prime is 261211577659. The next prime is 261211577677. The reversal of 261211577660 is 66775112162.

It is a super-2 number, since 2×261211577660² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 593662457 + ... + 593662896.

It is an arithmetic number, because the mean of its divisors is an integer number (24933832434).

Almost surely, 2^261211577660 is an apocalyptic number.

261211577660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261211577660 is an abundant number, since it is smaller than the sum of its proper divisors (337200400756).

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

261211577660 is a wasteful number, since it uses less digits than its factorization.

261211577660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1187325373 (or 1187325371 counting only the distinct ones).

The product of its (nonzero) digits is 211680, while the sum is 44.

The spelling of 261211577660 in words is "two hundred sixty-one billion, two hundred eleven million, five hundred seventy-seven thousand, six hundred sixty".