661043637 has 12 divisors (see below), whose sum is σ = 956891520. Its totient is φ = 439749288.

The previous prime is 661043627. The next prime is 661043671. The reversal of 661043637 is 736340166.

It is a happy number.

661043637 is a `hidden beast` number, since 6 + 6 + 10 + 4 + 3 + 637 = 666.

It is not a de Polignac number, because 661043637 - 2⁸ = 661043381 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661043627) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 74437 + ... + 82842.

It is an arithmetic number, because the mean of its divisors is an integer number (79740960).

Almost surely, 2^661043637 is an apocalyptic number.

It is an amenable number.

661043637 is a deficient number, since it is larger than the sum of its proper divisors (295847883).

661043637 is a wasteful number, since it uses less digits than its factorization.

661043637 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157752 (or 157749 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 36.

The square root of 661043637 is about 25710.7688916532. The cubic root of 661043637 is about 871.1174424433.

The spelling of 661043637 in words is "six hundred sixty-one million, forty-three thousand, six hundred thirty-seven".