2151020421 has 64 divisors (see below), whose sum is σ = 3841136640. Its totient is φ = 1173553920.

The previous prime is 2151020411. The next prime is 2151020429. The reversal of 2151020421 is 1240201512.

2151020421 is a `hidden beast` number, since 215 + 10 + 20 + 421 = 666.

It is not a de Polignac number, because 2151020421 - 2⁶ = 2151020357 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2151020394 and 2151020403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2151020429) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 106866 + ... + 125388.

It is an arithmetic number, because the mean of its divisors is an integer number (60017760).

Almost surely, 2^2151020421 is an apocalyptic number.

It is an amenable number.

2151020421 is a deficient number, since it is larger than the sum of its proper divisors (1690116219).

2151020421 is a wasteful number, since it uses less digits than its factorization.

2151020421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18583 (or 18577 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 2151020421 is about 46379.0946548119. The cubic root of 2151020421 is about 1290.8670374498.

Adding to 2151020421 its reverse (1240201512), we get a palindrome (3391221933).

The spelling of 2151020421 in words is "two billion, one hundred fifty-one million, twenty thousand, four hundred twenty-one".