1551551243021 has 32 divisors (see below), whose sum is σ = 1716251615232. Its totient is φ = 1393589292480.

The previous prime is 1551551242979. The next prime is 1551551243027. The reversal of 1551551243021 is 1203421551551.

It is a cyclic number.

It is not a de Polignac number, because 1551551243021 - 2²² = 1551547048717 is a prime.

It is a super-2 number, since 2×1551551243021² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1551551243027) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 329904356 + ... + 329909058.

It is an arithmetic number, because the mean of its divisors is an integer number (53632862976).

Almost surely, 2^{1551551243021} is an apocalyptic number.

It is an amenable number.

1551551243021 is a deficient number, since it is larger than the sum of its proper divisors (164700372211).

1551551243021 is a wasteful number, since it uses less digits than its factorization.

1551551243021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6873.

The product of its (nonzero) digits is 30000, while the sum is 35.

Adding to 1551551243021 its reverse (1203421551551), we get a palindrome (2754972794572).

The spelling of 1551551243021 in words is "one trillion, five hundred fifty-one billion, five hundred fifty-one million, two hundred forty-three thousand, twenty-one".