151321921 has 2 divisors, whose sum is σ = 151321922. Its totient is φ = 151321920.

The previous prime is 151321903. The next prime is 151321931. The reversal of 151321921 is 129123151.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 142086400 + 9235521 = 11920^2 + 3039^2 .

It is an emirp because it is prime and its reverse (129123151) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 151321921 - 2¹⁷ = 151190849 is a prime.

It is not a weakly prime, because it can be changed into another prime (151321931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 75660960 + 75660961.

It is an arithmetic number, because the mean of its divisors is an integer number (75660961).

Almost surely, 2^151321921 is an apocalyptic number.

It is an amenable number.

151321921 is a deficient number, since it is larger than the sum of its proper divisors (1).

151321921 is an equidigital number, since it uses as much as digits as its factorization.

151321921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 540, while the sum is 25.

The square root of 151321921 is about 12301.2975331873. The cubic root of 151321921 is about 532.8855558864.

The spelling of 151321921 in words is "one hundred fifty-one million, three hundred twenty-one thousand, nine hundred twenty-one".