102121921 has 4 divisors (see below), whose sum is σ = 111405744. Its totient is φ = 92838100.

The previous prime is 102121919. The next prime is 102121933. The reversal of 102121921 is 129121201.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 102121921 - 2¹ = 102121919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (102121951) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4641895 + ... + 4641916.

It is an arithmetic number, because the mean of its divisors is an integer number (27851436).

Almost surely, 2^102121921 is an apocalyptic number.

102121921 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

102121921 is a deficient number, since it is larger than the sum of its proper divisors (9283823).

102121921 is an equidigital number, since it uses as much as digits as its factorization.

102121921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9283822.

The product of its (nonzero) digits is 72, while the sum is 19.

The square root of 102121921 is about 10105.5391246583. The cubic root of 102121921 is about 467.4189604732.

The spelling of 102121921 in words is "one hundred two million, one hundred twenty-one thousand, nine hundred twenty-one".