661512843264 has 1248 divisors, whose sum is σ = 2433363932160. Its totient is φ = 155298299904.

The previous prime is 661512843259. The next prime is 661512843269. The reversal of 661512843264 is 462348215166.

It is an interprime number because it is at equal distance from previous prime (661512843259) and next prime (661512843269).

It is a tau number, because it is divible by the number of its divisors (1248).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661512843269) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 7432728532 + ... + 7432728620.

Almost surely, 2^661512843264 is an apocalyptic number.

661512843264 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661512843264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1216681966080).

661512843264 is an abundant number, since it is smaller than the sum of its proper divisors (1771851088896).

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

661512843264 is a wasteful number, since it uses less digits than its factorization.

661512843264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193 (or 154 counting only the distinct ones).

The product of its digits is 1658880, while the sum is 48.

The spelling of 661512843264 in words is "six hundred sixty-one billion, five hundred twelve million, eight hundred forty-three thousand, two hundred sixty-four".