16661777572540 has 12 divisors (see below), whose sum is σ = 34989732902376. Its totient is φ = 6664711029008.

The previous prime is 16661777572483. The next prime is 16661777572541. The reversal of 16661777572540 is 4527577716661.

It is a happy number.

It is a super-2 number, since 2×16661777572540² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16661777572541) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 416544439294 + ... + 416544439333.

It is an arithmetic number, because the mean of its divisors is an integer number (2915811075198).

Almost surely, 2^{16661777572540} is an apocalyptic number.

16661777572540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

16661777572540 is an abundant number, since it is smaller than the sum of its proper divisors (18327955329836).

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

16661777572540 is a wasteful number, since it uses less digits than its factorization.

16661777572540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 833088878636 (or 833088878634 counting only the distinct ones).

The product of its (nonzero) digits is 103723200, while the sum is 64.

The spelling of 16661777572540 in words is "sixteen trillion, six hundred sixty-one billion, seven hundred seventy-seven million, five hundred seventy-two thousand, five hundred forty".