121651621 has 16 divisors (see below), whose sum is σ = 149990400. Its totient is φ = 96081408.

The previous prime is 121651591. The next prime is 121651667. The reversal of 121651621 is 126156121.

It is a happy number.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121651621 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121651421) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 83820 + ... + 85258.

It is an arithmetic number, because the mean of its divisors is an integer number (9374400).

Almost surely, 2^121651621 is an apocalyptic number.

It is an amenable number.

121651621 is a deficient number, since it is larger than the sum of its proper divisors (28338779).

121651621 is a wasteful number, since it uses less digits than its factorization.

121651621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2388.

The product of its digits is 720, while the sum is 25.

The square root of 121651621 is about 11029.5793664128. The cubic root of 121651621 is about 495.4950270066.

The spelling of 121651621 in words is "one hundred twenty-one million, six hundred fifty-one thousand, six hundred twenty-one".