121287640 has 32 divisors (see below), whose sum is σ = 287262000. Its totient is φ = 45961344.

The previous prime is 121287631. The next prime is 121287709. The reversal of 121287640 is 46782121.

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, 79035 + ... + 80554.

Almost surely, 2^121287640 is an apocalyptic number.

121287640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121287640 is an abundant number, since it is smaller than the sum of its proper divisors (165974360).

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

121287640 is a wasteful number, since it uses less digits than its factorization.

121287640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159619 (or 159615 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 31.

The square root of 121287640 is about 11013.0667845065. The cubic root of 121287640 is about 495.0003605072. Note that the first 3 decimals are identical.

The spelling of 121287640 in words is "one hundred twenty-one million, two hundred eighty-seven thousand, six hundred forty".