101787921 has 45 divisors (see below), whose sum is σ = 163243641. Its totient is φ = 63197496.

The previous prime is 101787919. The next prime is 101787937. The reversal of 101787921 is 129787101.

The square root of 101787921 is 10089.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 101787921 - 2¹ = 101787919 is a prime.

It is not an unprimeable number, because it can be changed into a prime (101787971) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 1725190 + ... + 1725248.

Almost surely, 2^101787921 is an apocalyptic number.

101787921 is the 10089-th square number.

101787921 is the 5045-th centered octagonal number.

It is an amenable number.

101787921 is a deficient number, since it is larger than the sum of its proper divisors (61455720).

101787921 is an frugal number, since it uses more digits than its factorization.

101787921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168 (or 81 counting only the distinct ones).

The product of its (nonzero) digits is 7056, while the sum is 36.

The cubic root of 101787921 is about 466.9088236975.

Multiplying 101787921 by its sum of digits (36), we get a square (3664365156 = 60534²).

Multiplying 101787921 by its product of nonzero digits (7056), we get a square (718215570576 = 847476²).

The spelling of 101787921 in words is "one hundred one million, seven hundred eighty-seven thousand, nine hundred twenty-one".