661525642465 has 32 divisors (see below), whose sum is σ = 830499630336. Its totient is φ = 504895860480.

The previous prime is 661525642457. The next prime is 661525642483. The reversal of 661525642465 is 564246525166.

It is not a de Polignac number, because 661525642465 - 2³ = 661525642457 is a prime.

It is a super-2 number, since 2×661525642465² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 97552375 + ... + 97559155.

It is an arithmetic number, because the mean of its divisors is an integer number (25953113448).

Almost surely, 2^661525642465 is an apocalyptic number.

It is an amenable number.

661525642465 is a deficient number, since it is larger than the sum of its proper divisors (168973987871).

661525642465 is a wasteful number, since it uses less digits than its factorization.

661525642465 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8889.

The product of its digits is 10368000, while the sum is 52.

The spelling of 661525642465 in words is "six hundred sixty-one billion, five hundred twenty-five million, six hundred forty-two thousand, four hundred sixty-five".