121787931 has 16 divisors (see below), whose sum is σ = 164348064. Its totient is φ = 80216064.

The previous prime is 121787927. The next prime is 121787957. The reversal of 121787931 is 139787121.

It is not a de Polignac number, because 121787931 - 2² = 121787927 is a prime.

It is a super-2 number, since 2×121787931² = 29664600274521522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 121787931.

It is not an unprimeable number, because it can be changed into a prime (121787971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 105051 + ... + 106203.

It is an arithmetic number, because the mean of its divisors is an integer number (10271754).

Almost surely, 2^121787931 is an apocalyptic number.

121787931 is a deficient number, since it is larger than the sum of its proper divisors (42560133).

121787931 is a wasteful number, since it uses less digits than its factorization.

121787931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1550.

The product of its digits is 21168, while the sum is 39.

The square root of 121787931 is about 11035.7569291825. The cubic root of 121787931 is about 495.6800244494.

The spelling of 121787931 in words is "one hundred twenty-one million, seven hundred eighty-seven thousand, nine hundred thirty-one".